Source: WASHINGTON STATE UNIVERSITY submitted to
INTEGRATED DISEASE MANAGEMENT IN SMALL-SEEDED VEGETABLE SEED CROPS IN THE PACIFIC NORTHWEST
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1001737
Grant No.
(N/A)
Project No.
WNP00595
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Nov 22, 2013
Project End Date
Sep 30, 2018
Grant Year
(N/A)
Project Director
du Toit, LI, J.
Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001
Performing Department
Mt. Vernon Res & Ext Unit
Non Technical Summary
The Pacific Northwest (PNW) region of the USA supports one of the most abundant and diverse vegetable seed crop industries in the world. Of >50 types of vegetable seed crops grown in the PNW, at least 35 are for small-seeded vegetables. PNW seed crops produce 50% or more of the Brussels sprout, cabbage, cauliflower, carrot, radish, red beet, and spinach seed used in the USA, and 20-50% of the world supply depending on the species. Production of seed crops requires rigorous management practices to achieve the high standards of purity, germination, and freedom from seedborne pathogens necessitated by the global seed industry. Seedborne pathogens can cause economic losses for growers, are a liability for seed companies, and can disseminate pathogens into new areas or introduce different strains or races of pathogens into new regions. Seed crops also can be affected by pathogens that are not necessarily seedborne but can have a significant impact on seed yield and quality. Therefore, effective disease management remains a necessity for survival of a high quality seed industry in the PNW. A diversity of field, greenhouse, and lab research trials will be carried out on the primary diseases of concern for carrot seed crops (bacterial blight and powdery mildew, in particular), onion crops (particularly soilborne diseases as affected by soil fumigation practices common in central Washington), and spinach seed crops (Fusarium and Verticillium wilts, and two Phomopsis species of quarantine status that have impacted spinach seed trade significantly). In addition, the ability to work effectively with vegetable seed growers in the PNW on disease management will entail continued vigilance in monitoring the diseases of primary concern, as well as other diseases and new diseases that might become established on these crops, and how changes in production practices and seed industry policies impact the diseases; as well as continued research on identifying potential improvements in the efficacy, sustainability, and economic viability of disease management programs for the diversity of crops and diseases that affect these crops. Results will be presented at annual grower meetings, field days, conferences, and workshops, and published in relevant scientific journals, technical publications, and extension bulletins as well as the PNW Vegetable Extension Group (VEG) web site (http://mtvernon.wsu.edu/path_team/vegpath_team.htm). Information generated by this proposed research will be used to develop or refine regional IPM programs for diseases of small-seeded vegetable seed crops in the PNW. Identification of sources of inoculum, survival, means of dissemination, potential sources of resistance, and yield losses caused by the key pathogens will assist with implementing appropriate cultural, chemical, and other practices to reduce disease impacts. The carrot bacterial blight and powdery mildew resistance screening work is expected to increase our understanding of the nature of inheritance of different sources of resistance to these two diseases, assist breeders with incorporating resistance into carrot parent lines, commercial hybrids, and/or open pollinated lines, and provide growers with more carrot cultivars with resistance (ideally a greater level of resistance) to bacterial blight or powdery mildew than currently available. This should reduce bactericide and fungicide use, and the impacts of these diseases on carrot crops. Registration of fungicides or bactericides with greater efficacy, and optimizing the use of such products may reduce the number of applications needed for effective control of some diseases. The onion project is expected to elucidate the potential role of mycorrhizae in helping manage onion soilborne pathogens, particularly use of mycorrhizal inoculants in soils that have been fumigated. The results could be translated to applications of other mycorrhizal-forming species such as carrot. The spinach research is expected to facilitate a reasonable rotation interval between spinach seed crops (5 to 8 years instead of 10-15 years), without economic losses to Fusarium and Verticillium wilts, that could enable doubling of spinach seed production in the USA. The spinach Phomopsis project is expected to clarify whether strains of the two 'exotic' species of quarantine status are pathogenic on spinach and several other crop species, and identify potential method(s) of treating seed that kill the fungi and/or prevent seed transmission. The objective is to provide a means of overcoming the roadblock these fungi are causing to international spinach seed trade. The evolving nature of diseases that affect the PNW small-seeded vegetable seed industry highlights the continued need for a responsive research and extension program to investigate existing, new, and emerging diseases that affect vegetable seed production; develop integrated, economically-sound, and environmentally-sustainable approaches to disease management; and deliver research-based information effectively to the diversity of vegetable and seed stakeholders. The primary goals of the small-seeded vegetable seed pathology program at Washington State University are to help retain an economically-viable vegetable seed industry, and contribute towards a sustainable and secure food supply, both nationally and internationally. These goals are achieved through research and extension collaborations with WSU and other faculty and extension educators, as well as the vegetable and seed industries in the PNW, nationally, and internationally.
Animal Health Component
0%
Research Effort Categories
Basic
20%
Applied
75%
Developmental
5%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2121499116060%
2125240116040%
Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
5240 - Seeds and other plant propagules; 1499 - Vegetables, general/other;

Field Of Science
1160 - Pathology;
Goals / Objectives
Major Goals/Objectives The Pacific Northwest (PNW) region of the US supports one of the most abundant and diverse vegetable seed crop industries in the world. Of >50 types of vegetable seed crops grown in the PNW, at least 35 are for small-seeded vegetables. PNW seed crops produce 50% or more of the Brussels sprout, cabbage, cauliflower, carrot, radish, red beet, and spinach seed used in the US, and 20-50% of the world supply depending on the species. Production of seed crops requires rigorous management practices to achieve the high standards of purity, germination, and freedom from seedborne pathogens necessitated by the global seed industry. Seedborne pathogens can cause economic losses for growers, are a liability for seed companies, and can disseminate pathogens into new areas or introduce different strains or races of pathogens into new regions. Seed crops can also be affected by pathogens that are not necessarily seedborne but can have a significant impact on seed yield and quality. Therefore, effective disease management remains a necessity for survival of a high quality seed industry in the PNW. Significant progress was made by du Toit's program over the past 13 years at addressing some of the most important diseases that affect the vegetable seed industry in the PNW. The evolving nature of diseases that affect the PNW small-seeded vegetable seed industry highlights the continued need for a responsive research and extension program to investigate existing, new, and emerging diseases that affect vegetable seed production; develop integrated, economically-sound, and environmentally-sustainable approaches to disease management; and deliver research-based information effectively to the diversity of vegetable and seed stakeholders. The primary goals of the small-seeded vegetable seed pathology program are to help retain an economically-viable vegetable seed industry, and contribute towards a sustainable and secure food supply, both nationally and internationally. These goals are achieved through research and extension collaborations with WSU and other faculty and extension educators, as well as the vegetable and seed industries in the PNW, nationally, and internationally. Specific goals: A. CARROT SEED 1. Screen the USDA carrot Plant Introduction (PI) germplasm collection for resistance to X. hortorum pv. carotae, and backcross any putative resistant lines with public inbred lines for release to carrot breeding programs. 2. Continue evaluating bactericides and cultural practices for improved management of bacterial blight in carrot seed crops in the PNW. 3. Initiate a carrot powdery mildew resistance screening project in an effort to identify new potential sources of resistance to introgress into commercial carrot cultivars. B. ONION SEED Assess the impact of soil fumigation on mycorrhizal associations and soilborne diseases of onion in the Columbia Basin, and the potential role of mycorrhizal inoculants on alleviating adverse effects of soil fumigation, particularly for reducing the impact of soilborne diseases such as Rhizoctonia stunting and pink root. C. SPINACH SEED Examine additional potential management practices for Fusarium wilt and Verticillium wilt in spinach seed crops in the maritime PNW, including soil amendments (e.g., composts and green manure crops such as hairy vetch), additional organic and conventional fungicide treatments (seed, drench, and foliar applications), and selection of fertilizers (e.g., urea instead of ammonium nitrate, as the highly acidic nature of the latter reduces soil pH, which favors Fusarium wilt) to facilitate a reduction in rotation interval between spinach seed crops without exacerbating Verticillium wilt. 2. Identify spinach seed lots infested with either of the two quarantine species of Phomopsis/Diaporthe, Diaporthe viticola and D. melonis var. brevistylospora, evaluate potential organic and conventional fungicide seed treatments for treating infested lots, and assess the pathogenicity/host range of isolates of these two quarantine species on spinach and other pant species that might serve as hosts of these fungi. D. GENERAL 1. The ability to work effectively with vegetable seed growers in the PNW on disease management necessitates continued vigilance in monitoring the diseases of primary concern, as well as other diseases and new diseases that might become established on these crops, and how changes in production practices and seed industry policies impact the diseases; as well as continued research on identifying potential improvements in the efficacy, sustainability, and economic viability of disease management programs for the diversity of crops and diseases that affect these crops.
Project Methods
CARROT SEED Screen USDA carrot Plant Introduction (PI) germplasm for resistance to X. hortorum pv. carotae, backcross resistant and highly susceptible lines with inbred lines to assess the nature of resistance inheritance, and release the resistance to breeding programs: Seed of 68 carrot PIs from the USDA germplasm collection were planted in a greenhouse with seeds of 12 hybrids and open pollinated lines, and 2 inbred lines from breeder, Phil Simon. Up to 25 plants/entry were inoculated with X. hortorum pv. carotae (du Toit et al., 2005) and rated for severity of symptoms. Foliage of 5 plants/entry was tested for X. hortorum pv. carotae by dilution plating (du Toit et al., 2005). Mean CFU/g foliage was used to select the most resistant and most susceptible entries. Roots of these PIs and inbreds will be subjected to a second screening. PIs that demonstrate consistent resistant or susceptible reactions will be vernalized (4oC for 10-12 weeks), and crossed with the inbreds to begin back-crossing for evaluating inheritance of resistance. 2. Evaluate bactericides and other practices for management of bacterial blight in carrot seed crops Field and greenhouse trials will be set up with collaborators at Oregon State University and seed growers to assess efficacy of conventionaland organic batericides and disinfectants, timing of applications,steckling treatments, and cultural practices for managing bacterialblight. Inoculation, ratings, and seed assays will be carried out as done previously by du Toit's program. 3. Initiate a carrot powdery mildew resistance screening project to identify new sources of resistance to this disease, determine the inheritanceof resistance,andinitiate a backcrossing program to release the resistance to breeding programs: Similar to the bacterial blight project, carrot cultivars, breeding lines, and part of the USDA carrot PI collection will be screened for reactions to powdery mildew, and compared with 3-4 cultivars that carry the current source of resistance as well as susceptible cultivars. Plants will be inoculated in a greenhouse as done by du Toit and Derie (2007), and rated for severity of powdery mildew. Selected entries and control cultivars will be planted in a field with an infected, susceptible cultivar to assess powdery mildew reactions as affected by canopy morphology. Resistant lines will be vernalized and backcrossed to susceptible inbreds (along with susceptible lines) for determining inheritance of resistance. ONION SEED Assess the impact of soil fumigation on mycorrhizal associations and soilborne diseases of onion, and the potential role of mycorrhizal inoculants on alleviating adverse effects of soil fumigation, particularly soilborne diseases Conventional and organic onion crops will be surveyed over 2-3 years to determine Arbuscular Mycorrhizal Fungi (AMF) species diversity and abundance (5 conventional and 5 organic crops/season). Plant and soil samples will be collected from 4 sites/field. Soil characteristics (pH, organic matter, and nutrient levels) will be determined. Roots will be split into 2 subsamples, one for assessing AMF colonization (Vierhelig et al., 1998) and one for DNA extraction and AMF species identification using Glomerales-specific primers (Gorzelak et al., 2012). Soil from fields with AMF colonization will be used to extract AMF spores (Daniels and Skipper, 1982). The field inoculum and AMF inoculum from Plant Health LLC (Bob Linderman) will be used to establish cultures. Growth chamber studies will be carried out with soil from conventional and organic fields low in P. In one trial, a randomized complete block design will be used with 2 factors: 1) organic vs. conventional soil, and 2) AMF pre-plant soil inoculation with: a) AMF field isolate, b) AMF isolate from Plant Health LLC, and c) non-inoculated. Onion growth will be measured for each treatment. In a second study, effects of AMF colonization on onion stunting will be assessed using a randomized factorial block design with 2 factors: 1) organic vs. conventional soil, and 2) pre-plant soil inoculation: a) non-inoculated soil, b) R. solani AG8, c) AMF field isolate, d) AMF field isolate + R. solani AG8, e) AMF isolate from Plant Health LLC + R. solani AG8, and f) AMF isolate from Plant Health LLC. Onion growth and stunting from R. solani will be assessed. Percent AMF root colonization will be correlated with plant growth and soil treatments. Based on results, field trials will be carried out to determine how much AMF inoculations enhance onion growth and/or reduce the impact of soilborne diseases. SPINACH SEED Examine management practices for Fusarium and Verticillium wilts in spinach seed crops to reduce rotation intervals ~50%, to 5-8 years: A spinach seed crop field trial was initiated in 2013 in a grower's field to evaluate a local compost and the fungicide Proline for managing Fusarium and Verticillium wilts. Three female spinach lines (highly susceptible to partially resistant to Fusarium wilt, and the reverse for Verticillium wilt) were planted in a field with a 6-year rotation out of spinach. 2 tons limestone/acre were applied in 2012 and again in spring 2013. Grade A biosolids compost (City of La Conner) was applied (20 tons/acre), Proline was applied (3 times at 3-week intervals), or soil was not treated (control). Development of wilt, soil properties, spinach growth, seed yield, and harvested seed infected with wilt pathogens are being evaluated as done by du Toit's program since 2006. Results will be used to select additional treatments to evaluate in subsequent years. Based on preliminary evidence of a highly beneficial compost effect, regional sources of compost will be evaluated, as well as green manure crops (e.g., hairy vetch), and timing/rates of compost with limestone and fungicide seed/drench treatments. Growers' fields, along with a spinach Fusarium wilt soil bioassay provided annually as a service to growers, will provide further data on soil properties associated with these wilts. 2. Identify spinach seed lots infested with two quarantine species of Phomopsis/Diaporthe, Diaporthe viticola and D. meloni var. brevistylospora, evaluate organic/conventional seed treatments, and assesspathogenicity ofisolates of these species on spinach and other crops. Spinach seed was received to identify lots with Phomopsis/Diaporthe species (>25,000 seeds/lot inspected for pycnidia). Seeds with pycnidia will be incubated on blotters or media, and examined microscopically for alpha and beta conidia of Phomopsis. Seed treatments to be evaluated, depending on how muchinfested seed can be procured/quarantine species): non-treated seed; organic treatments such as hot water,chlorine, KleenGrow (quartenary ammonium chloride), Tsunami 100 (hydrogen peroxide + peroxyacetic acid), OxiDate Broad Spectrum Bactericide/Fungicide (hydrogen dioxide), Thermogard (steam treatment); and conventional treatments such as Thiram 42-S (thiram) + Apron (metalaxyl), Farmore D300 (azoxystrobin + fludioxonil + mefenoxam), Farmore D300 + Mertect 340F (thiabendazole), Rancona Spinach (ipconazole) + Apron, Coronet (boscalid + pyraclostrobin + Apron), Maxim 4FS (fludioxonil) + Apron, and Dynasty 100FS (azoxystrobin) + Apron. For each treatment, 3 assays will be done: 1) freeze blotter seed health assay, 2) seed germination assay, and 3) seed grow-out assay (latter for the best treatments), using 4 replicates of 100 seeds/treatment/assay/lot. Lastly, isolates of the exotic Phomopsis spp. will be tested for pathogenicity on spinach and other crop species of concern (by Jim Correll, University of Arkansas). Spinach seedlings will be tested using: 1) hypcocotyl wound inoculation, 2) foliar inoculation of vegetative plants, and 3) inoculation of flowering plants. Pathogenicity on other hosts: grapevine (van Niekerk et al., 2005); melon (Bruton, 1996); and soybean (Mengistu et al., 2007) at seedling, R5, and R7 growth stages.

Progress 11/22/13 to 09/30/18

Outputs
Target Audience:Vegetable and vegetable seed growers, vegetable seed industry personnel, extension personnel, researchers, consultants, graduate and undergraduate students, postdoctorates, and technical staff. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Attendance at professional meetings for presenting results, networking with specialists on specific crops/diseases, and providing graduate students and technical staff with professional development opportunities, including presenting their research and learning extension/communication skills. Paid for 1 graduate student and 1 Scientific Assistant Sr. to attend the International Congress of Plant Pathology in Boston, MA to present their research projects. MS student, Alex Batson, is spending 6 weeks at the University of Amsterdam to annotate the genome of 12 isolates of a fungus for his thesis project, in collaboration with a Fusarium genomicist, Dr. Martijn Rep. How have the results been disseminated to communities of interest?See the list of service and event noted in 'Other Products' above. Numerous presentations, workshops, field days, seminars, etc. were held throughout the year in grower/stakeholder meetings, scientific meetings, etc. Presented 18 research/extension talks, 16 of which were invited (including in Italy, South Africa, Spain, and various states). Participated in or led 10 workshops, field days, webinars, and tours. Diagnosed 120 plant samples with accompanying management recommendations to producers in WA, nationally, and internationally. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? CARROT SEED: Continued a 4-year USDA OREI carrot project with PD Phil Simon from the Univ. of WI. Serving as co-PI on this organic carrot breeding project. Helped evaluate carrot breeding lines for susceptibility to motley dwarf in a field trial in Chimacum, WA. Also continued a 4-year USDA SCRI grant on carrot breeding with co-PI Tim Waters and PD Phil Simon to screen the USDA NPGS carrot germplasm collection for resistance to cavity spot. Planted a second year of a nursery cavity spot trial in Othello, WA. Due to poor stand issues and lack of adequate disease pressure, initiated a new cavity spot trial site in Mount Vernon, WA after fumigating the soil with metam sodium in late September, and then infesting the site with inoculum in late October. The trial will be inoculated again in spring 2019 and planted with carrot breeding lines. Also tested a root inoculation protocol in conjunction with carrot breeders from private industry to compare with the field nursery results. ONION SEED: 1) Finished a 3-year WSDA SCBG project on evaluating arbuscular mycorrhizal fungi (AMF) inoculants for enhancing onion production in the Columbia Basin. Published results showing that that moderate to high soil P levels typically used by onion growers in this region significantly reduce root colonization by AMF, negating the benefits of AMF inoculants in onion crops. Set up a field trial in Pasco, WA to evaluate products for control of downy mildew in onion bulb production. Generated infected plants using inoculum obtained off an infected, overwintered onion seed crop. Warm, dry conditions in the Columbia Basin in 2018 limited development of downy mildew to the point there was inadequate disease to differentiate efficacy of the products. SPINACH SEED: 1) The 9th Annual Spinach Fusarium Wilt Soil Bioassay was completed in the winter of 2017-18, with soil samples from 55 growers' fields in Washington assayed for the level of risk of Fusarium wilt for spinach seed crops to be planted in 2018. To date, >350 fields have been tested for risk of this disease because of the highly conducive nature of acid soils in this region to Fusarium wilt, which can cause complete losses of spinach seed crops planted with susceptible parent lines, even after 15 + years of rotation out of spinach. 2) With an MS student, Alex Batson, screened isolates of the spinach Fusarium wilt pathogen for potential effector genes in the Secreted in Xylem (SIX) family of genes to try and understand if any of these effectors contribute to the ability of this fungus to cause disease on spinach. Two fo the 14 known SIX genes were detected, but the combination of genes and the gene sequences were not unique enough to differentiate isolates of this pathogen from non-pathogenic isolates also obtained off spinach plants. Therefore, the genome has been sequenced for 7 isolates of the pathogen and 5 non-pathogenic spinach isolates using Illuminoseq and PacBio sequencing. Alex is working with a Fusarium genomicist at the Univ. of Amsterdam to annotate the sequences, identify putative effector genes. The results should help advance efforts to breed for resistance to spinach Fusarium wilt, and to develop molecular markers for rapid/efficient detection and differentiation of isolates of this pathogen from closely related fungi. GENERAL: 1) Provided diagnosis and associated management recommendations for 120 samples from vegetable growers in the Pacific Northwest. 2) Communicated with brassica vegetable seed growers on 3 quarantine seedborne pathogens found in WA in 2018. One, black leg caused by Phoma lingam, turned out to be a false positive as a result of misidentification of the fungus by Iowa State University Seed Testing lab. I verified the misidentification and worked with the lab to get the results retracted and a corrected phytosanitary certified issues to the seed grower and affected seed company. A retraction was also submitted to Capital Press because of a previous article noting that this quarantine disease had been found in western WA. This was important to restore the reputation of this region as a black leg-free area for seed production. Also helped a grower and surrounding producers ensure effective management of crop residues in a brassica field in which black rot, another quarantine seedborne pathogen, was detected in 2018 (provided the definitive diagnosis for the grower and worked with the WSDA Seed Program inspectors on the diagnosis and recommended management practices). Also diagnosed bacterial brown spot in a bean seed crop in the Columbia Basin, where this is a quarantine disease, for the WSDA Seed Program. 3) Worked with a Japanese intern, Haruka Fukada, to publish a Disease Note documenting the first report of Phomopsis black root rot of cucumber in the USA, which was detected in an organic cucumber crop in western WA. 4) Two former graduate students in my program, Shannon Carmody and John Weber, obtained employment with private industry. Accepted an MS student and a PhD student in my program to work on vegetable seed pathology projects (sweet corn and spinach).

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Fukada, H., Derie, M.L., Shishido, M, and du Toit, L.J. 2018. Phomopsis black root rot of cucumber in Washington State caused by Diaporthe sclerotioides. Plant Disease 102:1657.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Knerr, A.J., Wheeler, D., Schlatter, D., Sharma-Poudyal, D., du Toit, L.J., and Paulitz, T.C. 2018. Arbuscular mycorrhizal fungal communities in organic and conventional onion crops in the Columbia Basin of the Pacific Northwest USA. Phytobiomes 2: in press. http://dx.doi.org/10/.1094/PBIOMES-05-18-0022-R
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Batson, A.M., Peever, T.L., and du Toit, L.J. 2018. Determining the genetic basis of pathogenicity of Fusarium oxysporum f. sp. spinaciae on spinach. Abstract for International Spinach Conference, 14-16 Feb. 2018, Murcia, Spain. https://spinach.uark.edu/spain-presentations/
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Batson, A.M., Peever, T.L., and du Toit, L.J. 2018. The Secreted in Xylem gene profile of the spinach Fusarium wilt pathogen. International Congress of Plant Pathology, 29 Jul.-5 Aug. 2018, Boston, MA. Phytopathology 108:S1.207 https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-108-10-S1.1
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Derie, M.L., Tymon, L., and du Toit, L.J. 2018. Occurrence of bacterial pathogens, including non-toxigenic starins of Pseudomonas syringae pv. phaseolicola, in bean seed crops in Washington State. International Congress of Plant Pathology, 29 Jul.-5 Aug. 2018, Boston, MA. Phytopathology 108:S1.127. https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-108-10-S1.1
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. 2018. Spinach seed production in the Pacific Northwest USA. Invited presentation at International Spinach Conference, 14-16 Feb. 2018, Murcia, Spain. https://spinach.uark.edu/spain-presentations/
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J., and Correll, J.C. 2018. Case studies of the complexity of seedborne and seed transmitted fungi affecting regional and global seed trade. Guest speaker, joint symposium of American Phytopathological Society (APS) and Societ� Italiana di Patologia Vegetale (SIPaV), 24th National Congress of SIPaV, 5-7 Sep. 2018, Ancona, Italy.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J., and Derie, M.L. 2018. Evaluation of natamycin seed treatments for Stemphylium botroyosum and other necrotrophic fungi on spinach seed. International Spinach Conference, 14-16 Feb. 2018, Murcia, Spain. https://spinach.uark.edu/spain-presentations/
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Koenick, L., Knight, N., Vaghefi, N., du Toit, L., and Pethybridge, S. 2018. Genetic structure of Phoma betae populations in New York and Washington States, USA. International Congress of Plant Pathology, 29 Jul.-5 Aug. 2018, Boston, MA. Phytopathology 108:S1.87. https://apsjournals.apsnet.org/doi/pdf/10.1094/PHYTO-108-10-S1.1
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Shi, A., Correll, J., Feng, C., Mou, B., Avila, C., du Toit, L., Stein, L., Hogan, R., Qin, J., Zhou, W., Battharai, G., Zia, B., Waltram, R., Weng, Y., Liu, B., and Gyawali, S. 2018. Developing genetic and molecular resources to improve spinach prodcution and management. Annu. Meeting American Soc. Hortic. Sci., 30 Jul.-3 Aug. 2018, Washington, DC.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Simon, P., Colley, M., McKenzie, L., Zystro, J., McCluskey, C., Hoagland, L., Silva, E., Roberts, P., Dawson, J., du Toit, L., Waters, T., and Nunez, J. 2018. CIOA 2 - Carrot Improvement for Organic Agriculture with Added Grower and Consumer Value. Annu. Meeting American Soc. Hortic. Sci., 30 Jul.-3 Aug. 2018, Washington, DC.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Simon, P., Ellison, S., Spooner, D., Senalik, D., Colley, M., McKenzie, L., Dawson, J., Tanumihardjo, S., Nunez, J., Roberts, P., van Deynze, A., Sumner, D., Matthews, W., Lee, H., Iorizzo, M., du Toit, L., Waters, T., and Diaz-Ramirez, J. 2018. Identifying phenotypes, markers, and genes in carrot germplasm to deliver improved carrots to growers and consumers. Annu. Meeting American Soc. Hortic. Sci., 30 Jul.-3 Aug. 2018, Washington, DC.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: du Toit, L.J., Derie, M.L., and Holmes, B.J. 2018. Evaluation of natamycin seed treatments for Stemphylium, Verticillium, and other fungi on spinach seed, 2017. Plant Disease Management Reports 12:ST003.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: du Toit, L.J., Derie, M.L., Holmes, B.J., and Batson, A. 2018. Evaluation of natamycin seed treatments for Stemphylium botryosum and other necrotrophic fungi on spinach seed, 2017. Plant Disease Management Reports 12:V050.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: du Toit, L.J., Derie, M.L., Holmes, B.J., and Correll, J.C. 2018. Evaluation of seed treatments for Colletotrichum dematium, Stemphylium botryosum, and Verticillium dahliae on spinach seed, 2017. Plant Disease Management Reports 12:V051.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: du Toit, L.J., Derie, M.L., Holmes, B.J., Henrichs, B.A., Winkler, L.R., Waters, T.D., and Darner, J. 2018. The effects of arbuscular mycorrhizal fungal inoculants on pink root and yield in an onion crop near Paterson, WA, 2016. Plant Disease Management Reports 12:V102.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: du Toit, L.J., Derie, M.L., Holmes, B.J., and Stearns, T. 2018. Steam treatments for necrotrophic fungi on spinach seed, 2017. Plant Disease Management Reports 12:ST004.
  • Type: Other Status: Published Year Published: 2018 Citation: du Toit, L., and Yorgey, G. 2018. Onion stunting after cereal cover crops. Page 6. Timing of glyphosate applications to wheat cover crops to reduce onion stunting caused by Rhizoctonia solani. Page 7. Efficacy of fungicide applications to manage onion stunting caused by Rhizoctonia spp. Pages 7-8. In: Strip-tillage for onions and sweet corn, Lorin Grigg. Farmer to Farmer Case Study Series on Increasing Resilience among Farmers in the Pacific Northwest. Washington State University Extension PNW702.
  • Type: Other Status: Published Year Published: 2018 Citation: Fukada, H., and du Toit, L.J. 2018. Cucumber  black root rot. Page 4C-91 in: 2018 Pacific Northwest Pacific Northwest Disease Management Handbook, J.W. Pscheidt and C.M. Ocamb, editors. A Pacific Northwest Extension Publication, Oregon State University, Washington State University, University of Idaho. https://pnwhandbooks.org/plantdisease/host-disease/cucumber-cucumis-sativa-black-root-rot
  • Type: Other Status: Accepted Year Published: 2018 Citation: Winkler, L., du Toit, L., and Waters, T. 2018. Do onion growers benefit from mycorrhizal inoculants ? The effects of mycorrhizal inoculants on onion crops in the Columbia Basin. Onion World Nov. 2018: in press.
  • Type: Websites Status: Published Year Published: 2018 Citation: Wohleb, C.H., Waters, T.W., and du Toit, L.J. 2018. Washington State University Extension Onion Alerts. Contributed disease information and photos for WSU Onion Alerts released online on 24 Apr., 23 May, 31 May, 3 Jul., 16 Aug., 27 Aug., 1 Oct., and 31 Oct. 2018. https://us13.campaign-archive.com/?u=2eff8714011ff4bfba18a0704&id=d75dc96e7f
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Management of Fusarium basal rot of onion. Invited presentation, Onion Session of the Pacific Northwest Vegetable Association Annual Convention and Trade Show, 14-15 Nov. 2018, Kennewick, WA. (200 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Regionally appropriate fungicide programs for common onion pathogens in the Columbia Basin. Invited presentation, Onion Session of the Pacific Northwest Vegetable Association Annual Convention & Trade Show, 14-15 Nov. 2018, Kennewick, WA. (200 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J., Solemslie, R, and Waters, T. Early season diseases and pests of sweet corn in the Columbia Basin. Invited presentation, General Vegetable Session of the Pacific Northwest Vegetable Association Annual Convention & Trade Show, 14-15 Nov. 2018, Kennewick, WA. (85 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Impact of fungicides on plant health. Invited presentation, Pest Management Session of the Pacific Northwest Vegetable Association Annual Convention & Trade Show, 14-15 Nov. 2018, Kennewick, WA. (175 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Complexities and synergies in large-scale conventional and organic agriculture in Washington. Invited presentation, Organic Session of the Pacific Northwest Vegetable Association Annual Convention & Trade Show, 14-15 Nov. 2018, Kennewick, WA. (150 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Case studies of the complexity of seedborne and seed transmitted fungi affecting regional and global seed trade. Guest speaker at the joint symposium of the American Phytopathological Society (APS) and the Societ� Italiana di Patologia Vegetale (SIPaV), 24th National Congress of SIPaV, 5-7 Sep. 2018, Ancona, Italy. (see Abstracts above) (~250 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Diseases in Brassica vegetable seed crops in the Pacific Northwest. Invited presentation to Bejo Zaden Brassica Team, 3 May 2018, Mount Vernon, WA. (20 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Complexities and synergies in large-scale conventional and organic agriculture in Washington. Organic Fresh Food Panel. Invited presentation at Spring 2018 University Industry Consortium Meeting, 24-27 Apr. 2018, Walter Clore Wine & Culinary Center, Prosser, WA. (75 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Conventional and organic disease control strategies for specialty crops. Invited presentation at 2018 Colorado Fruit & Vegetable Growers Association Annual Meeting, 19-20 Feb. 2018, Denver, CO (50 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Allium, bean, and crucifer seed quarantines in Washington: Current status and future needs. Annual Basin Producers 2018 Pesticide Recertification Day, 19 Jan. 2018, Moses Lake, WA (175 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. A review of onion diseases  identification and management. 4-hour invited presentation at the 2018 Walla Walla Onion Growers Meeting organized by CHS Primeland, 18 Jan. 2018, Walla Walla, WA (12 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Allium, bean, and crucifer seed quarantines in Washington: Current status and future needs. Columbia Basin Crop Consultants Assoc. Short Course, 17 Jan. 2018, Moses Lake, WA (150 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Seedborne and seed transmitted plant pathogens. Columbia Basin Crop Consultants Assoc. Short Course, 17 Jan. 2018, Moses Lake, WA (100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Whats the deal with black leg of brassicas? Columbia Basin Vegetable Seed Assoc. Annual Meeting, 16 Jan. 2018, Moses Lake, WA (70 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Batson, A., and du Toit, L.J. 2018. Fusarium oxysporum f. sp. spinaciae: What makes this a pathogen of spinach? Western Washington Seed Workshop and Puget Sound Seed Growers Association Annual Meeting, 12 Jan. 2018, Mount Vernon, WA. (90 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. 2018. Battles of the brassicas: Common brassica diseases in western Washington. Invited presentation for a Hot Topic session at Focus on Farming XV, Snohomish Co. Extension, 8 Nov. 2018, Monroe, WA. (50 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: du Toit, L.J. Bacterial diseases in Washington's bean seed crops. Columbia Basin Vegetable Seed Assoc. Annual Meeting, 16 Jan. 2018, Moses Lake, WA (70 people)


Progress 10/01/16 to 09/30/17

Outputs
Target Audience:Vegetable and vegetable seed growers, vegetable seed industry personnel, extension personnel, researechers, consultants, graduate and undergraduate students, postdoctorates, and technical staff. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Attendance at professional meetings for presenting results, networking with specialists on specific crops/diseases, and providing graduate students and technical staff with professional development opportunities, including presenting their research and learning extension/communication skills. Paid for 2 graduate students to attend the national meeting of the American Phytopathological Society. How have the results been disseminated to communities of interest?See the list of service and event noted in 'Other Products' above. Numerous presentations, workshops, field days, seminars, etc. were held throughout the year in grower/stakeholder meetings, scientific meetings, etc. Presented 23 research/extension talks, 13 of which were invited (including in Chile, South Africa, and Denmark). Participated in or led 10 workshops, field days, webinars, and tours, including a spinach workshop in Denmark and one in the Netherlands. Diagnosed 103 plant samples with accompanying management recommendations to producers in WA, nationally, and even internationally. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? CARROT SEED: Started a new 4-year USDA OREI carrot project with PD Phil Simon from the Univ. of WI. Serving as co-PI on this organic carrot breeding project, and a new 4-year USDA SCRI grant on carrot breeding with co-PI Tim Waters to screen the USDA NPGS carrot germplasm collection for resistance to cavity spot. ONION SEED: 1) Demonstrated that soil P level has a significant impact on the degree of root colonization of onions by arbuscular mycorrhizae fungi (AMF), potentially negating the benefits of AMF inoculants in onion crops because of the relatively high levels of fertilizer applied. In collaboration with Teresa Coutinho, phytobacteriologist at the Univ. of Pretoria in South Africa, and Valery Moloto, PhD student in her lab, a paper was published on Pseudomonas syringae strains from onion plants and seed in South Africa that caused lesions on leaves and seed stalks. Metabolic, genetic (multilocus sequence typing), and pathogenic tests on onion, chive, leek, and spring onion separated the strains into two groups, one supporting a new pathovar of P. syringae, P. syringae pv. allii, and the other corresponding to P. syringae pv. porri, a known pathogen of onion and other Allium spp. Strains of pv. allii were pathogenic only on onion, but pv. porri strains were pathogenic on all four Allium spp. Symptoms caused by strains of the two pathovars were indistinguishable. This is the first documentation of two pathovars on Allium spp. SPINACH SEED: 1) The 8th Annual Spinach Fusarium Wilt Soil Bioassay: In the winter of 2016-17, soil samples from 33 fields in western Washington were assayed for the level of risk of Fusarium wilt for spinach seed crops to be planted in 2016. To date, >270 fields have been tested for relative risk of this disease because of the highly conducive nature of acid soils in this region to Fusarium wilt, which can cause complete losses of spinach seed crops planted with susceptible parent line(s), even following 15 + years of rotation out of spinach. 2) Published a 4-year field trial examining how to optimize suppression of Fusarium wilt of spinach, caused by Fusarium oxysporum f. sp. spinaciae, using limestone amendments. Demonstrated that annual applications of limestone on acid soils can reduce rotation intervals by 50%, potentially doubling the capacity for spinach seed production in the USA. 3) Recruited an MS student in 2017 to screen for pathogenicity genes in the spinach Fusarium wilt fungus, to understand what makes this fungus pathogenic on spinach, advance efforts to breed for resistance to spinach Fusarium wilt, and develop molecular markers for rapid/efficient detection and differentiation of isolates of this pathogen from closely related fungi. GENERAL: 1) With PhD student, Bethany Econopouly, published the first report of downy mildew of buckwheat in the USA, after observing the disease in buckwheat trials in Skagit Co., WA as well as growers' fields in several counties in western WA. 2) Isolates of the blackleg pathogen obtained from a certified organic Brassica rapa seed crop in the Willamette Valley in 2014 were demonstrated, with Dilantha Fernando at Univ. of Manitoba, to be Leptosphaeria biglobosa isolates with a different virulence profile from six known subclades of this species. Genetic and pathogenicity studies supporting a new proposed subclade, 'americensis', were completed. A Plant Dis. Note was published documenting blackleg in the dryland region eastern WA. 3) MS student, S. Carmody, found light leaf spot and white leaf spot in B. juncea cover crops and B. rapa weeds in western WA in 2016, first reports in this state. Carmody demonstrated the light leaf spot fungus can be seedborne and seed transmitted, and identified organic and conventional seed treatments that limit the risk of introducing the pathogen on seed. Carmody also showed isolates of this pathogen in the USA are a different species than in the EU/UK and Oceano, and provided evidence for naming a new species, Pyrenopeziza cascadia.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Paulitz, T.C., Knerr, A.J., Carmody, S.M., Schlatter, D., Sowers, K., Derie, M.L., and du Toit, L.J. 2017. First report of Leptosphaeria maculans and Leptosphaeria biglobosa, causal agents of blackleg, on canola in Washington State. Plant Disease 101:504.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2018 Citation: Simon, P.W., Navazio, J.P., Colley, M., McCluskey, C., Zystro, J., Hoagland, L., Roberts, P.A., du Toit, L.J., Waters, T., Silva, E., Colquhoun, J., and Nunez, J. 2017. The CIOA (Carrot Improvement for Organic Agriculture) Project: Location, cropping system, and genetic background influence carrot performance, including top height and flavor. Acta Horticulturae: in press.
  • Type: Other Status: Published Year Published: 2017 Citation: du Toit, L.J. 2017. Evaluation of onion disease management practices and opportunities for enhanced onion disease management in Sacapulas, Quich�, Guatemala. Report for the Farmer-2-Farmer Program of the US Agency for International Development, following a 2-week volunteer project with onion farmers in the highlands of Guatemala. 19 pp.
  • Type: Book Chapters Status: Published Year Published: 2017 Citation: du Toit, L.J., Gilbertson, R.L., Asma, M., and Schaad, N.W. 2017. Detection of Xanthomonas hortorum pv. carotae in carrot seed. Chapter 20, pages 133-142, In: Detection of Plant Pathogenic Bacteria in Seed and Planting Material. M. Fatmi, R.R. Walcott, and N.W. Schaad, editors. American Phytopathological Society, St. Paul, MN.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Carmody, S.M., and du Toit, L.J. 2017. Seed treatments to eradicate Pyrenopeziza brassicae from infected mustard (Brassica juncea) seed. Poster 295-P, 2017 APS Annual Meeting, 5-9 Aug. 2017, San Antonio, TX.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Carmody, S.M., King, K.M., Claassen, B.J., Fraaije, B.A., West, J.S., Ocamb, C.M., and du Toit, L.J. 2017. Genetic analysis of Pyrenopeziza brassicae, cause of light leaf spot of brassicas, in the European Union, Oceania, and North America. Poster 536-P, 2017 APS Annual Meeting, 5-9 Aug. 2017, San Antonio, TX.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Moloto, V.M., Goszczynska, T., du Toit, L.J., and Coutinho, T.A. 2017. A new pathovar of Pseudomonas syringae, pathovar allii, isolated from onion plants exhibiting symptoms of blight. European Journal of Plant Pathology 146:591-603.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Koenick, L., Vaghefi, N., Knight, N., du Toit, L.J., and Pethybridge, S. 2017. Development of microsatellite markers for quantifying genetic diversity of Pleospora betae. Oral presentation, 2017 APS Northeastern Division Meeting, 1-3 Nov. 2017, Quebec City, Canada.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Liu, B., Feng, C., Manley, A., Garcia Rodriguez, R., Stein, L., Cochran, K., du Toit, L., and Correll, J. 2017. Survey of spinach leaf spot diseases in Texas. Poster 427-P presented at 2017 APS Annual Meeting, 5-9 Aug. 2017, San Antonio, TX.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Miles, N., du Toit, L.J., and Compton, B. Necrotrophic fungi associated with seed of a traditional food plant, great camas (Camassia leichtlinii), at a tribal college. Student poster presented at the 2017 Pacific Northwest COSMOS Summit: Collaborations Across Our Communities (National Science Foundation Alliances for Graduate Education and the Professoriate project no. 1432932), 12-14 Oct. 2017, Bozeman, MT.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Weber, J.M., and du Toit, L.J. 2017. Effect of Contans WG application and burial of sclerotia on survival of sclerotia of Sclerotinia sclerotiorum in the Columbia Basin of central Washington. Poster 51-P presented at 2017 APS Annual Meeting, 5-9 Aug. 2017, San Antonio, TX.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Spinach seed crop pathology research and extension at Washington State University: Engaging principles of the U.S. Land Grant Mission to enhance production of a minor acreage, high value crop. Inivited paper presented for J.E. Vanderplank Memorial Address, 50th Anniv. Congress Southern African Soc. Plant Pathology, 15-18 Jan. 2017, Champagne Sports Resort, Drakensburg, South Africa.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Moloto, V.M., Goszczynska, T., du Toit, L.J., and Coutinho, T.A. 2017. Analysis of bacterial communities associated with onion (Allium cepa) seeds through culture dependent and culture independent methods. Poster presented at 50th Anniversary Congress of the Southern African Society for Plant Pathology, 15-18 Jan. 2017, Champagne Sports Resort, Drakensburg, South Africa.
  • Type: Other Status: Published Year Published: 2017 Citation: du Toit, L.J., Vincelli, P., and Munkvold, G. 2017. Watch for changes to the committee meeting schedule at the 2017 APS meeting in San Antonio, TX. Phytopathology News 51:78-79.
  • Type: Other Status: Published Year Published: 2017 Citation: du Toit, L.J., Vincelli, P., Munkvold, G., and Tedford, E. 2017. Time to get involved with APS! Phytopathology News 51:79.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Evaluating irrigation management and bactericides for internal dry scale and bacterial bulb rots of onion. Invited presentation, Pacific Northwest Vegetable Association Annual Convention & Trade Show, 15-16 Nov. 2017, Kennewick, WA. (125 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Identification of foliar plant pathogens. Invited presentation, Pacific Northwest Vegetable Association Annual Convention & Trade Show, 15-16 Nov. 2017, Kennewick, WA. (100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Lessons from onion downy mildew and Stemphylium leaf blight. Invited presentation, Pacific Northwest Vegetable Association Annual Convention & Trade Show, 15-16 Nov. 2017, Kennewick, WA. (125 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Whats the big deal with black leg of brassicas? Invited presentation, Pacific Northwest Vegetable Association Annual Convention & Trade Show, 15-16 Nov. 2017, Kennewick, WA. (120 people)
  • Type: Other Status: Published Year Published: 2017 Citation: du Toit, L.J. Brassica light leaf spot, white leaf spot, and black leg; onion neck rot; and bacterial blight of carrot. Invited presentation to Bejo Seeds production team, 7 Nov. 2017, Mount Vernon, WA. (30 people)
  • Type: Other Status: Published Year Published: 2017 Citation: du Toit, L.J. Wilt diseases: Managing persistent pathogens in high value vegetable seed crops. Invited seminar to Department of Plant Pathology, North Carolina State University, 9 Oct. 2017, Raleigh, NC. (60 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Got seed? Plant pathology research and extension contributions to the Pacific Northwest Vegetable Seed Industry. Invited presentation at the Congreso LatinoAmericano de Fitopatolog�a, 2-5 Oct. 2017, Concepcion, Chile. (200 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Seedborne vs. seed transmitted: The curious case of Phomopsis in spinach. Invited contribution to Phytoviews session at 2017 APS annual meeting, 5-9 Aug. 2017, San Antonio, TX. Other panelists were Wayne Wiebe and Christina Devorshack, representing industry and regulatory perspectives on seedborne vs. seed transmitted microorganisms. (100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. The What? Why? And How? Of Onion Disease Management in the Columbia Basin. Invited presentation at the National Onion Association Summer Meeting, 20 Jul. 2017, Richland, WA. (~150 people)
  • Type: Other Status: Published Year Published: 2017 Citation: du Toit, L.J. Vegetable seed crop pathology research, and the role the Washington State Commission for Pesticide Registration (WSCPR) funding plays in supporting this program. Invited presentation to WSCPR board, 24 May 2017, La Conner, WA. (12 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. It takes two to tango: Management of Stemphylium leaf blight and downy mildew in the onion leaf blight complex. Invited by University of Wisconsin faculty to speak at Wisconsin Potato & Vegetable Growers Association Grower Education Conference, 7-9 Feb. 2016, Stevens Point, WI. (Presentation by Skype to ~30 onion stakeholders)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J., and Carmody, S. Light leaf spot and white leaf spot on brassica crops in western Washington. Wilbur Ellis Growers Meeting, 2 Feb. 2017, La Conner, WA. (100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. Spinach seed crop pathology research and extension at Washington State University: Engaging principles of the U.S. Land Grant Mission to enhance production of a minor acreage, high value crop. J.E. Vanderplank Memorial Address, 50th Anniv. Congress Southern African Soc. Plant Pathologists, 15-18 Jan. 2017, Champagne Sports Resort, Drakensburg, South Africa. (~200 attendees, see Abstracts above)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: du Toit, L.J. 2017. Downy mildew in onion seed crops. Columbia Basin Vegetable Seed Assoc. Annual Meeting, 1 Feb. 2017, Moses Lake, WA. (85 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Weber, J., and du Toit, L.J. White mold in sunflower seed crops. Columbia Basin Vegetable Seed Assoc. Annual Meeting, 1 Feb. 2017, Moses Lake, WA. (85 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Derie, M.L., and du Toit, L.J. 2017. Phoma betae in table beet and Swiss chard seed crops in western Washington. Puget Sound Seed Growers Association Annual Meeting, 13 Jan. 2017, Mount Vernon, WA. (100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Carmody, S.M., and du Toit, L.J. 2017. Light leaf spot and white leaf spot on brassicas in the Pacific Northwest. Puget Sound Seed Growers Association Annual Meeting, 13 Jan. 2017, Mount Vernon, WA. (100 people)
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Gatch, E.W., and du Toit, L.J. 2017. Limestone-mediated suppression of Fusarium wilt in spinach seed crops. Plant Disease 101:81-94.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Econopouly, B.F., Derie, M.L., Jones, S.S., and du Toit, L.J. 2017. Downy mildew of buckwheat, Fagopyrum esculentum, in the USA caused by Peronospora cf. documetii. Plant Disease 101:391


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:Vegetable and vegetable seed growers, vegetable seed industry personnel, extension personnel, researechers, consultants, graduate and undergraduate students, postdoctorates, and technical staff. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Attendance at professional meetings for presenting results, networking with specialists on specific crops/diseases, and providing graduate students and technical staff with professional development opportunities, including presenting their research and learning extension/communication skills. Paid for 2 graduate students and a research intern to attend a seed health workshop in Portland, OR in spring 2016. Mike Derie, Scientific Assistant, attended the 2016 APS Annual Meeting where he presented a poster, attended a molecular diagnostic workshop, and participated in numerous sessions and seminars. Mike was promoted to Scientific Assistant Sr. in 2016. How have the results been disseminated to communities of interest?See the list of service and event noted in 'Other Products' above. Numerous presentations, workshops, field days, seminars, etc. were held throughout the year in grower/stakeholder meetings, scientific meetings, etc. I presented 21 research/extension talks, 13 of which were invited (including 1 in Canada, 1 in CA, 1 in ID, 1 in MO, 3 in OR, 1 in FL). I also participated in or led 12 workshops, field days, webinars, and tours. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? CARROT SEED: Finished 4-year a USDA OREI carrot project with PI Phil Simon from the Univ. of WI. Serving as co-PI on a new 4-year OREI grant on organic carrot breeding, and a new 4-year USDA SCRI grant on carrot breeding to work with co-PI Tim Waters to screen the USDA NPGS carrot germplasm collection for resistance to cavity spot. ONION SEED: 1) Presented a poster at APS annual meeting on arbuscular mycorrhizal fungi communities in organic and conventional onion fields in the Columbia Basin, because of the potential negative impacts of some practices used in conventional onion production (e.g., soil fumigation) on beneficial soil microflora like AMF. The survey indicated AMF were similarly present in 4 organic and 4 conventional onion bulb crops. Next-generation sequencing used to identify AMF taxa in both systems showed diversity was not significantly different between the two systems, but community composition differed. Claroideoglomus lamellosum, Glomus mossae and Glomus Whitfield type were the most dominant. C. lamellosum was decreased in fumigated fields, along with Glomus Whitfield type, but G. mossae was increased. In terms of organic vs. conventional fields, Glomus Mo 17 seems to be decreased in organic fields, but G. Whitfield type was increased in organic fields. 2) The effects of four commercial AMF products on onion growth were evaluated in a growth chamber trial for onion root colonization by AMF, and shoot height and dry weight: i) BioTerra Plus, ii) MycoApply Ultrafine Endo, iii) Mykos Gold Granular, and iv) MykePro Granular. Onions in soil amended with Mykos Gold Granular were taller, had greater shoot dry weight, were colonized extensively by AMF, and had significantly greater foliar nutrient levels compared to plants in control soil without AMF treatment. Mykos Gold Granular was the only product that consistently improved onion growth and AMF root colonization. The liquid formulation did not lead to onion root colonization. In 2016, five onion trials were completed in growers' fields to evaluate the potential use of AMF inoculants for increasing P use efficiency, reducing severity of soilborne pathogens, and promoting onion growth. Results indicated AMF treatments generally did not improve stand, bulb yield, pink root control, or foliar nutrient content significantly. However, high levels of soil P may have negated potential benefits of AMF. 3) Onion stunting caused by Rhizoctonia spp. is an important soilborne disease on sandy soils in the Columbia Basin where cereal winter cover crops are planted the previous fall to prevent wind erosion of soil. The cover crop is killed with a herbicide shortly before or after onion seeding in spring. The dead cereal plants protect onion seedlings against sand-blasting, but the cover crop provides a bridge for Rhizoctonia spp. on dead cereal roots to colonize onion roots, causing onion stunting. To determine the effect of herbicide application to reduce this green bridge, three glyphosate application timing intervals preceding onion planting were evaluated. As the interval between herbicide application and onion planting increased from 3 to 27 days, the number of patches of stunted onion plants decreased by =55%, total area of stunted patches decreased by 54-63%, and patch severity decreased by 59-65%. Increasing the interval between herbicide application to the cover crop and onion planting is a practical strategy to avoid onion stunting. 4) In collaboration with Teresa Coutinho, phytobacteriologist at the Univ. of Pretoria in South Africa, and Valery Moloto, PhD student in her lab, a paper was published on Pseudomonas syringae strains from onion plants and seed in South Africa that caused lesions on leaves and seed stalks. Metabolic, genetic (multilocus sequence typing), and pathogenic tests on onion, chive, leek, and spring onion separated the strains into two groups, one supporting a new pathovar of P. syringae, P. syringae pv. allii, and the other corresponding to P. syringae pv. porri, a known pathogen of onion and other Allium spp. Strains of pv. allii were pathogenic only on onion, but pv. porri strains were pathogenic on all four Allium spp. Symptoms caused by strains of the two pathovars were indistinguishable. This is the first documentation of two pathovars on Allium spp. SPINACH SEED: 1) The 7th Spinach Fusarium Wilt Soil Bioassay: In the winter of 2015-16, soil samples from >30 fields in northwestern Washington were assayed for the level of risk of Fusarium wilt for spinach seed crops to be planted in 2016. Samples from an additional 33 fields were submitted in Dec. 2016 to be tested in 2017 in the 8th offering of this annual bioassay. To date, >270 fields have been tested for relative risk of this disease because of the highly conducive nature of acid soils in this region to Fusarium wilt, which can cause complete losses of spinach seed crops planted with susceptible parent line(s), even following 15 years of rotation out of spinach. 2) Fusarium wilt of spinach, caused by Fusarium oxysporum f. sp. spinaciae, is favored by acid soils in which the fungus can survive >10 years. The 10- to 15-year rotations required to minimize losses to Fusarium wilt are the primary constraint on spinach seed production in the maritime Pacific Northwest, the only region of the USA suitable for this cool-season, daylength sensitive crop. Raising soil pH with agricultural limestone gives a transitory, partially suppressive effect on Fusarium wilt. Three successive annual applications of limestone at 4.48 tons/ha reduced wilt incidence by ~20%, increased spinach biomass by 33%, and increased marketable spinach seed yield by 45% compared with plots amended once with the same rate of limestone. The suppressive effect increased with increasing rate of limestone amendment, with the greatest difference between 0 and 2.24 tons limestone/ha applied annually for 3 years. The effects differed among female lines varying in susceptibility to Fusarium wilt. Annual applications of limestone on acid soils can reduce rotation intervals by 50%, potentially doubling the capacity for spinach seed production in the USA. 3) Obtained funding and recruited an MS student to start a project in 2017 on screening for pathogenicity factors in the spinach Fusarium wilt fungus, to understand what makes this fungus pathogenic on spinach, advance efforts to breed for resistance to spinach Fusarium wilt, and develop molecular markers for rapid/efficient detection and differentiation of isolates of this pathogen from closely related fungi. 3) Efficacy and phytotoxicity data from 2 years of field trials in western WA resulted in a Special Local Needs 24(c) registration for prothioconazole for Fusarium wilt in spinach seed crops in WA and OR. GENERAL: 1) With PhD student, Bethany Econopouly, published (in press) the first report of downy mildew of buckwheat in the USA, after observing the disease in buckwheat trials in Skagit Co., WA and growers' fields in several counties in western WA. 2) Isolates of the blackleg pathogen obtained from a certified organic Brassica rapa seed crop in the Willamette Valley in 2014 were demonstrated, with Dilantha Fernando at Univ. of Manitoba, to be Leptosphaeria biglobosa isolates with a different virulence profile from six known subclades of this species. Genetic and pathogenicity studies supporting a new proposed subclade, 'americensis', were completed and a paper submitted to Phytopathology (accepted Dec. 2016 pending revisions). A Plant Dis. Note is in press documenting blackleg in the dryland region eastern WA. 3) MS student, S. Carmody, found light leaf spot and white leaf spot in B. juncea cover crops and B. rapa weeds in western WA in 2016, first reports in this state. Carmody demonstrated the light leaf spot fungus can be seedborne and seed transmitted, and is evaluating organic and conventional seed treatments to limit risks of introducing the pathogen on seed.

Publications

  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Gatch, E.W., and du Toit, L.J. 2017. Limestone-mediated suppression of Fusarium wilt in spinach seed crops. Plant Disease 101:81-94.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Econopouly, B.F., Derie, M.L., Jones, S.S., and du Toit, L.J. 2017. Downy mildew of buckwheat, Fagopyrum esculentum, in the USA caused by Peronospora cf. documetii. Plant Disease: in press. PDIS-09-16-1362-PDN.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Paulitz, T.C., Knerr, A.J., Carmody, S.M., Schlatter, D., Sowers, K., Derie, M.L., and du Toit, L.J. 2017. First report of Leptosphaeria maculans and Leptosphaeria biglobosa, causal agents of blackleg, on canola in Washington State. Plant Disease: in press. PDIS-08-16-1108-PDN.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Simon, P.W., Navazio, J.P., Colley, M., McCluskey, C., Zystro, J., Hoagland, L., Roberts, P.A., du Toit, L.J., Waters, T., Silva, E., Colquhoun, J., and Nunez, J. 2017. The CIOA (Carrot Improvement for Organic Agriculture) Project: Location, cropping system, and genetic background influence carrot performance, including top height and flavor. Acta Horticulturae: in press.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Alcala, A.C., Paulitz, T.C., Schroeder, K.L., Porter, L.D., Derie, M.L., and du Toit, L.J. 2016. Pythium species associated with damping-off of pea in certified organic fields in the Columbia Basin of central Washington. Plant Disease 100:916-925.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Moloto, V.M., Goszczynska, T., du Toit, L.J., and Coutinho, T.A. 2016. A new pathovar of Pseudomonas syringae, pathovar allii, isolated from onion plants exhibiting symptoms of blight. European Journal of Plant Pathology 146: doi:10.1007/s10658-016-1028-1.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Sharma-Poudyal, D., Paulitz, T.C., and du Toit, L.J. 2016. Timing of glyphosate applications to wheat cover crops to reduce onion stunting caused by Rhizoctonia solani. Plant Disease 100:1474-1481.
  • Type: Other Status: Published Year Published: 2016 Citation: Carmody, S.M., and du Toit, L.J. 2016. Management of light leaf spot and white leaf spot in brassica crops in the Pacific Northwest. Seed Matters/Clif Bar Family Foundation Progress Report, Nov. 2016. 7 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: Carmody, S., and du Toit, L.J. 2016. Seed transmission and management of white leaf spot and light leaf pathogens of brassicas in the Pacific Northwest. Western SARE Project GW16-055 Mid-Year Progress Report, Jan. 2016. 5 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, L.J. 2016. Identification and management of downy mildew in onion bulb and seed crops in the Columbia Basin. Pp. 6-7 in: 2016 WSU Onion Cultivar Demonstration and Field Day Handout, 25 Aug. 2016, Othello, WA. 16 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, L.J., and Waters, T.W. 2016. Irrigation management for control of onion internal dry scale and bacterial bulb rots. Pp. 10-11 in: 2016 WSU Onion Cultivar Demonstration and Field Day Handout, 25 Aug. 2016, Othello, WA. 16 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, L.J., Waters, T.W., Derie, M.L., and Henrichs, B. 2016. The potential role of mycorrhizal inoculants in Columbia Basin onion production. Pp. 8-9 in: 2016 WSU Onion Cultivar Demonstration and Field Day Handout, 25 Aug. 2016, Othello, WA. 16 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, L.J., Waters, T.W., Derie, M.L., Henrichs, B., and Holmes, B. 2016. The potential role of mycorrhizal inoculants in Columbia Basin onion production. Annual progress report for the Washington State Department of Agriculture Specialty Crop Block Grant, Nov. 2016. 14 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, LJ., Correll, J.C., Derie, M.L., Pavel, J., and Feng, C. 2016. Phomopsis on spinach seed: Evaluation of a seed health assays, efficacy of seed treatments, and pathogenicity of seed isolates on spinach. Project report, American Seed Trade Associations American Seed Research Fund, July 2016. 26 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, L.J., Gilijamse, E., Oosterhof, J., Hiddink, G., and Politikou, L. 2016. 7-0XX. Detection of Verticillium dahliae on Spinacia oleracea (spinach) seed. Annexe to Chapter 7: Seed Health Testing Methods, International Rules for Seed Testing. International Seed Testing Association, Bassersdorf, Switzerland. 11 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: Paulitz, T. C., Knerr, A. J., Schlatter, D., Sowers, K., Derie, M. and du Toit, L. 2016. A survey of eastern Washington State for blackleg disease of canola caused by Leptosphaeria maculans and Leptosphaeria biglobosa. Pp. 27-28 in: 2016 Field Day Abstracts, Dept. of Crop and Soil Sciences, Tech. Rep. 16-1.
  • Type: Other Status: Published Year Published: 2016 Citation: Waters, T.W., du Toit, L.J., Pappu, H.R., and Wohleb, C.H. 2015. 2015 Annual report for Washington State Participants in the W2008 multi-state project. Jan. 2016. 6 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: Waters, T.W., du Toit, L.J., Wohleb, C.H., and Pappu, H.R. 2016. 2016 Annual report for Washington State participants in the W2008 multistate project. Dec. 2016. 5 pp.
  • Type: Book Chapters Status: Awaiting Publication Year Published: 2016 Citation: du Toit, L.J., Gilbertson, R.L., Asma, M., and Schaad, N.W. 2016. Detection of Xanthomonas hortorum pv. carotae in carrot seed. Chapter 26. In: Detection of Plant Pathogenic Bacteria in Seed and Planting Material. M. Fatmi, R.R. Walcott, and N.W. Schaad (editors). APS Press, St. Paul, MN. 22 pages. In press.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Carmody, S.M., Ocamb, C.M., and du Toit, L.J. 2016. Potential seed transmission of Pyrenopeziza brassicae and Mycosphaerella capsellae in brassicas in the Pacific Northwest USA. Paper presented at American Phytopathological Society (APS) Pacific Division Meeting, 28-30 Jun. 2016, La Conner, WA. Phytopathology 106:S4.196 (Abstr.)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: du Toit, L.J. 2016. Spinach Fusarium wilt: Management of a tenacious, soilborne pathogen based on Achilles heel. Paper presented at 2016 International Spinach Conference, 29 Nov.1 Dec. 2016, San Antonio, TX.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: du Toit, L.J. Tapping into growers expertise: Effective engagement in extension. 2016 APS Annual Meeting, 30 Jul.3 Aug. 2016, Tampa, FL. Invited paper presented in APS Graduate Student Committees Fieldside Manners special session. Phytopathology 106:S4.177-178. (Abstr.)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: du Toit, L.J., Waters, T.W., Derie, M.L., Henrichs, B.A., and Holmes, B.J. 2016. Assessing the potential value of mycorrhizal inoculants in onion production in the Columbia Basin of Washington, USA. Paper presented at National Onion Association Convention and National Allium Research Conference, 30 Nov.  3 Dec. 2016, Savannah, GA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Derie, M.L., Holmes, B.J., Safni, I, Bull, C.T., and du Toit, L.J. 2016. Seedborne inoculum thresholds of Pseudomonas syringae pv. aptata, causal agent of bacterial leaf spot, in baby leaf Swiss chard crops. Poster presented at 2016 APS Annual Meeting, 30 Jul.3 Aug. 2016, Tampa, FL. Phytopathology 106:S4.142 (Abstr.)
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Gatch, E.W., Derie, M.L., Holmes, B.J., and du Toit, L.J. 2016. Effect of Proline on Fusarium wilt in a spinach seed crop in western Washington, 2012. Plant Disease Management Reports 10:V103.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Knerr, J.A., Paulitz, T.C., and du Toit, L.J. 2016. Effects of commercial arbuscular mycorrhizae fungi (AMF) products on onion in a growth chamber study, 2015. Plant Disease Management Reports 10:V098.
  • Type: Websites Status: Published Year Published: 2016 Citation: Schwartz, H.F., du Toit, L.J., and Coutinho, T. Diseases of Onion and Garlic (Allium cepa L. and A. sativum L., respectively). APS Common Names of Plant Diseases. American Phytopathological Society, St. Paul, MN. http://www.apsnet.org/publications/commonnames/Pages/OnionandGarlic.aspx
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: : Sharma-Poudyal, D., Paulitz, T., Porter, L., and du Toit, L. 2016. Screening of pea genotypes for resistance to root rot caused by Rhizctonia solani AG 8, 2012. Plant Disease Management Reports 10:FC184.
  • Type: Other Status: Published Year Published: 2016 Citation: Carmody, S., and du Toit, L.J. 2016. Light leaf spot and white leaf spot  two new fungal diseases of brassicas in the PNW. Tilth Producers Quarterly 26 (4):5,18,20.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, L.J., Tedford, E., and Vincelli, P. 2016. APS Councilors Challenge 2016 : Engaging the diversity of APS membership. Phytopathology News 50 (5):60.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Knerr, A.J., Wheeler, D., Schlatter, D., Paulitz, T., and du Toit, L.J. 2016. Arbuscular mycorrhizal fungal communities associated with organic and conventional onion crops in the Columbia Basin of Washington. Poster presented at 2016 APS Annual Meeting, 30 Jul.3 Aug. 2016, Tampa, FL. Phytopathology 106:S4.35. (Abstr.)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Safni, I., Sepulveda, L.R., Goldman, P.H., Derie, M.L., du Toit, L.J., Koike, S.T., Stockwell, V.O., and Bull, C.T. 2016. Genetic diversity of Pseudomonas syringae causing bacterial leaf spot on table beet (Beta vulgaris) and Swiss chard (Beta vulgaris subsp. cicla). Poster presented at 2016 APS Annual Meeting, 30 Jul.3 Aug. 2016, Tampa, FL. Phytopathology 106:S4.143. (Abstr.)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Weber, J.M., Chen, T., Chen, W., and du Toit, L.J. 2016. Clonality within disease foci and field populations of Sclerotinia sclerotiorum causing basal stalk rot in sunflower seed crops in central Washington. Poster presented at APS Pacific Division Meeting, 28-30 Jun. 2016, La Conner, WA. Phytopathology 106:S4.207.
  • Type: Other Status: Published Year Published: 2016 Citation: du Toit, L.J., Waters, T., and Reitz, S. 2016. Internal dry scale and associated bulb rots of onion. Extension Bulletin PNW686. 8 pp.
  • Type: Other Status: Published Year Published: 2016 Citation: Vincelli, P., du Toit, L.J., and Munkvold, G. 2016. APS Councilors Challenge 2017: Growing our diverse society. Phytopathology News 50 (10):135.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: du Toit, L.J. 2016. Black leg in the Pacific Northwest: Status of the WSDA Crucifer Quarantine. Proceedings of the Pacific Northwest Direct Seed Association Cropping Systems Conference, 12-13 Jan. 2016, Kennewick, WA. 2 pp. http://www.directseed.org/events/annual-conference/
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Ocamb, C.M. and du Toit, L.J. 2016. Managing seedborne pathogens: Black leg in brassica crops in the Pacific Northwest and implications for the organic seed industry. Pp. 90-95 in: Proceedings of the 8th Organic Seed Growers Conference, 4-6 Feb. 2016, Corvallis, OR. http://seedalliance.org/events/organic_seed_growers_conference
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Simon, P., Colley, M., McKenzie, L., Zystro, J., McCluskey, C., Hoagland, L., Roberts, P., Colquhoun, J., du Toit, L., Nunez, J., Silva, E., and Waters, T. The CIOA (Carrot Improvement for Organic Agriculture) Project: New sources of nematode resistance and evidence that location, cropping system, and genetic background influence carrot performance. Pp. 26-31 in: Proceedings of the 8th Organic Seed Growers Conf., 4-6 Feb. 2016, Corvallis, OR. http://seedalliance.org/events/organic_seed_growers_conference
  • Type: Websites Status: Published Year Published: 2016 Citation: 2009-16 (1) * du Toit, L.J., Inglis, D.A., and Ostrander, C. Pacific Northwest Vegetable Extension Group (PNW VEG) website: http://mtvernon.wsu.edu/path_team/vegpath_team.htm (revised regularly)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Spinach seed health and production practices. Invited presentation to Spinach Committee, California Seed Association Annual Meeting, 21-23 Mar. 2016, Napa, CA. (45 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: du Toit, L.J. Onion white rot quarantine update. Columbia Basin Vegetable Seed Assoc. Annual Meeting, 22 Jan. 2015, Moses Lake, WA. (60 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: du Toit, L.J. Update on brassica black leg in the PNW. Columbia Basin Vegetable Seed Assoc. Annual Meeting, 22 Jan. 2015, Moses Lake, WA. (60 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Weber, J., and du Toit, L.J. Research efforts to enhance management of white mold in sunflower seed crops. Columbia Basin Vegetable Seed Assoc. Annual Meeting, 22 Jan. 2015, Moses Lake, WA. (60 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Diagnosing plant problems  Not so elementary, dear Watson! Columbia Basin Crop Consultants Assoc. Short Course, 13-14 Jan. 2016, Moses Lake, WA. (85 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Onion internal dry scale and management of culled bulbs. Columbia Basin Crop Consultants Assoc. Short Course, 13-14 Jan. 2016, Moses Lake, WA. (85 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Brassica black leg  The hidden dangers of a seedborne pathogen. Invited by American Seed Trade Association to speak at Western Seed & Lawn Conference because of increasing prevalence of black leg in canola crops in Midwestern states, and concern about infected brassica seed in cover crop seed lots. 6 Nov. 2016, Kansas City, MO. (75 cover crop stakeholders)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Mycorrhizal inoculants in onion production: Possibilities and pitfalls? 65th Muck Vegetable Growers Conference, 12-13 Apr. 2016, Bradford, Ontario, Canada. (75 growers)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Carrot diseases in the Pacific Northwest. Pacific Northwest Vegetable Association Annual Convention & Trade Show, 16-17 Nov. 2016, Kennewick, WA. (100 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Evaluation of arbuscular mycorrhizae in commercial onion fields. Pacific Northwest Vegetable Association Annual Convention & Trade Show, 16-17 Nov. 2016, Kennewick, WA. (150 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Market opportunities for organic production in the PNW. Represented WSU in a 90 minute panel discussion with representatives from Charlies Produce, Costco, Oregon Dept. of Agriculture, Oregon Tilth, Walmart, Whole Foods, Washington State Dept. of Agriculture. Pacific Northwest Vegetable Association Annual Convention & Trade Show, 16-17 Nov. 2016, Kennewick, WA. (150 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: du Toit, L.J. Bacterial blight of table beet and Swiss chard: Efforts to quantify seedborne inoculum thresholds. Puget Sound Seed Growers Association Annual Meeting, 29 Jan. 2016, Mount Vernon, WA. (50 people)
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Carmody, S., and du Toit, L.J. Seedborne inoculum for light leaf spot and white leaf spot of brassicas in the Pacific Northwest: Potential significance and management. Puget Sound Seed Growers Association Annual Meeting, 29 Jan. 2016, Mount Vernon, WA. (50 people)


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:Vegetable and vegetable seed growers, vegetable seed industry personnel, extension personnel, researchers, consultants, graduate and undergraduate students, postdoctorates, technical staff. Changes/Problems:Difficulties with the formulations of commercial mycorrhizal products available to growers not being compatible with the onion planting equipment limited the ability to get effective evaulation of mycorrhizal inoculations in onion growers fields in 2015. Three meetings were held with onion and carrot growers in fall 2015 to look at how a diversity of commercial products can be tested with their planting equipment in field trials in 2016. Discussions are still ongoing with USDA APHIS PPQ about the quarantine status of the two Phomopsis/Diaporthe species found on spinach seed to date, given that one species is known to occur in olive trees in CA. What opportunities for training and professional development has the project provided?Attendance at professional meetings for presenting results, networking with specialists on the crops/diseases, and providing graduate students, and technical staff with opportunities to present their results and learn from growers and related agricultural stakeholders. How have the results been disseminated to communities of interest?See the list of service and events noted in 'Other Products' above. Numerous presentations, workshops, field days, seminars, etc. were held throughout the year in WA, OR, AZ, CA, NY, and Argentina. What do you plan to do during the next reporting period to accomplish the goals?Continue as planned, with modifications as described above.

Impacts
What was accomplished under these goals? CARROT SEED 1) Published a paper in HortScience on screening a subset of the USDA carrot Plant Introduction (PI) germplasm collection for resistance to Xanthomonas hortorum pv. carotae (MS student, Eric Christianson's thesis project). Plant breeders from a number of vegetable seed companies have contacted us about the more resistant accessions identified, to include in their breeding efforts. 2) Continued to provide input to Dr. J. Dung at Oregon State University on research on carrot bacterial blight, including screening potential bactericides, and optimizing the timing and application of products. Reviewed about 5 grant proposals he prepared for commodity and federal funding agencies. 3) Did not initiate a carrot powdery mildew resistance screening project in an effort to identify new potential sources of resistance to introgress into commercial carrot cultivars because the proposal submitted to the CA Fresh Carrot Advisory Board in 2014 was not funded. Continued the last of 4 years of research for a USDA OREI grant with 4 cooperating states to evaluate selection of carrot breeding lines under organic and conventional production conditions in each state. Assisted with disease evaluations in the replicated plots in each site in WA, including powdery mildew, Cercospora leaf spot, and bacterial blight. Examined microscopically samples of carrot foliage from the trials in WI and IN. ONION SEED 1) Assess the impact of soil fumigation on mycorrhizal associations and soilborne diseases of onion in the Columbia Basin, and the potential role of mycorrhizal inoculants on alleviating adverse effects of soil fumigation, particularly for reducing the impact of soilborne diseases such as Rhizoctonia stunting and pink root: Surveyed 4 conventional and 5 certified organic fields used for onion bulb crops in 2014 were surveyed for mycorrhizae by sampling soil just prior to planting, and sampling onion plants in each field at mid-bulbing. Onion plants grown in soil from each field were used to bait mycorrhizae, and the roots stained for quantifying mycorrhizal colonization. Mycorrhizae were observed in all fields at high incidences, with similar colonization of roots between organic and conventional fields, which suggests conventional production practices may not adversely affect mycorrhizal populations or the populations rebound relatively rapidly, particularly after soil fumigation. Pyrosequencing was used to identify AMF genera in both systems, with greater abundance of Glomerales in organic vs. conventional fields, and greater abundance of Glomus spp. in the former. To assess the impact of soil fumigation with metam sodium on AMF, soil was sampled from each of 4 pairs of growers' fields in the Columbia Basin prior to fumigation in fall 2014, and again at planting in spring 2015. The soils were baited with onions and the roots stained for AMF colonization assessment. There were no significant differences in AMF colonization in fumigated vs. non-fumigated fields. Pyrosequencing is being used to assess differences in AMF genera/families colonizing onions grown in soil from these fumigated vs. non-fumigated fields. Applied for and received a WSDA SCBG for 2.5 years of research on using AMF to enhance onion and carrot production. Held three meetings with onion growers in fall 2015 to assess how commercial AMF products can be applied in large-scale field rials with their planting equipment to enable objective, fair evaluation of the products. Recruited a postdoc to start on the project in spring 2016. 2) Set up onion neck rot and black mold fungicide efficacy trials with T. Waters to screen fungicides for efficacy against these important storage rots. Bulbs are in storage for evaluation in Feb. 2016. Others: Published a paper in Plant Disease on onion stunting caused by Rhizoctonia spp., including the species and subspecies of 251 isolates from 29 onion fields that were identified by DNA sequencing; and quantified the yield loss caused by these fungi in growers' onion bulb crops. A second paper in HortScience described screening 35 onion genotypes for resistance to stunting caused by Rhizoctonia solani AG 8. Only four genotypes had partial resistance, and could be used in onion breeding programs. SPINACH SEED 1) Examine additional potential management practices for Fusarium wilt and Verticillium wilt in spinach seed crops in the maritime PNW: Published a paper in Plant Disease from former PhD student, Emily Gatch's dissertation on a soil bioassay for predicting the risk of spinach Fusarium wilt in growers' fields. Completed the 6th annual offering of this bioassay in winter 2014-15, and initiated the 7th offering in winter 2015-16. Almost 250 fields in northwestern WA have now been tested with this bioassay since it was developed, with growers paying $200/field for the assay. Stakeholders have verified that none of the fields tested in this assay and demonstrated to be 'safe' for planting have resulted in major losses to Fusarium wilt, whereas some fields that were not included in the bioassay have resulted in catastrophic crop losses. 2) Identify spinach seed lots infested with either of the two quarantine species of Phomopsis/Diaporthe, Diaporthe viticola and D. melonis var. brevistylospora, evaluate potential organic and conventional fungicide seed treatments for treating infested lots, and assess the pathogenicity/host range of isolates of these two quarantine species on spinach and other pant species that might serve as hosts of these fungi: In collaboration with J. Correll at Univ. of Arkansas, demonstrated that >25 isolates of these fungi were not pathogenic on spinach and grape. Presented results of these tests and seed treatment assays at ASTA Vegetable & Flower Conference. Still working with ASTA and USDA APHIS PPQ mycologists on the quarantine status of these fungi, despite the fact that some have now been documented to occur naturally in the USA. 3) Results of two years of fungicide trials with prothioconazole were used to apply for a SLN 24(c) registration in spinach seed crops in WA and OR, and also provided documentation in support of SLN registrations of this fungicide in brassica seed crops in both states to manage black leg following the 2014 and 2015 epidemic in the Willamette Valley. The OR Dept. of Agriculture spinach and brassica registrations were approved in Jan. 2016, and the WSDA applications are being processed. GENERAL: See list of products and other products for many publications, presentations, workshops, field days, tours, websites, etc. in 2015 in support of the PNW vegetable and seed industries. Also published a paper in Plant Disease on Rhizoctonia spp. associated with stunted patches in processing pea crops and pea seed crops in the Columbia Basin, and yield losses caused by this disease in pea. Three additional manuscripts submitted in 2015 have been accepted for publication in 2016.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: 3. Gatch, E.W., and du Toit, L.J. 2015. A soil bioassay for predicting the risk of spinach Fusarium wilt. Plant Disease 99:512-526.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: 4. Sharma-Poudyal, D., Paulitz, T.C., and du Toit, L.J. 2015. Evaluation of onion genotypes for resistance to stunting caused by Rhizoctonia solani AG 8. HortScience 50:551-554.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: 5. Sharma-Poudyal, D., Paulitz, T.C., and du Toit, L.J. 2015. Stunted patches in onion bulb crops in Oregon and Washington: Etiology and yield loss. Plant Disease 99:648-658.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: 6. Sharma-Poudyal, D., Paulitz, T.C., Porter, L.D., and du Toit, L.J. 2015. Characterization and pathogenicity of Rhizoctonia and Rhizoctonia-like species from pea crops in the Columbia Basin of Oregon and Washington. Plant Disease 99:604-613.
  • Type: Other Status: Published Year Published: 2015 Citation: 7. du Toit, L.J., Derie, M.L., and Holmes, B.J. 2015. 2014 Carrot cavity spot Serenade Soil trial. Research report submitted to Bayer CropScience, Feb. 2015. 7 pp.
  • Type: Other Status: Published Year Published: 2015 Citation: 8. du Toit, L.J. and Derie, M.L. 2015. 2014 Onion pink root Serenade Soil efficacy trial in Connell, Washington. Research report submitted to Bayer CropScience, Feb. 2015. 4 pp.
  • Type: Other Status: Published Year Published: 2015 Citation: 9. Gilijamse, E., du Toit, L.J., Hiddink, G., Brown, P., Oosterhof, J., and Asma, M. 2015. Methods for the detection of Verticillium dahliae on spinach seeds. Version 1.0, Nov. 2015. International Seed Federation, Bassersdorf, Switzerland. 11 pp.
  • Type: Other Status: Published Year Published: 2015 Citation: 10. Pappu, H.R., Waters, T.D., Wohleb, C.H., and du Toit, L.J. 2015. W2008 accomplishments for 2014 by Washington State participants. Jan. 2015. 6 pp.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 11. Collins, B.D., McDonald, M.R., du Toit, L.J., and Westerveld, S. 2015. Evaluation of management practices for Fusarium wilt in bunching spinach production in Ontario, Canada. 2015 International Spinach Conference, 24-25 Feb. 2015, Yuma, AZ. http://uark.edu/ua/spinach/registration/index.html (ABSTRACT)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 12. du Toit, L.J., Derie, M.L., Correll, J.C., and Feng, C. 2015. Phomopsis/Diaporthe and spinach seed: History, concerns, and research update. 2015 International Spinach Conference, 24-25 Feb. 2015, Yuma, AZ. http://uark.edu/ua/spinach/registration/index.html (ABSTRACT)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 13. du Toit, L.J., Derie, M.L., Youngquist, C.P., and Holmes, B.J. Suppression of Fusarium wilt in spinach seed production using compost. 2015 International Spinach Conference, 24-25 Feb. 2015, Yuma, AZ. http://uark.edu/ua/spinach/registration/index.html (ABSTRACT)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 14. Simon, P., Colley, M., McKenzie, L., Zystro, J., Hoagland, L., Roberts, P., Colquhoun, J., du Toit, L., Nunez, J., Silva, E., and Waters, T. 2015. Cultivar development with the CIOA (Carrot Improvement for Organic Agriculture) project targets flavor, novel colors, top height, and disease and pest resistance. 37th Internat. Carrot Conf., 15-17 Sep. 2015, Nottawasaga Inn Resort & Conf. Centre, Alliston, Ontario, Canada. (ABSTRACT)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 15. Sowers, K., Paulitz, T., Davis, J., du Toit, L., Schroeder, K., and Wysocki, D. Blackleg in canola  Reason for alarm in Washington State? Abstract for 2015 WSU Lind Dryland Field Day, 11 Jun. 2015, Lind, WA; and Spillman Dryland Field Day, 14 Jul. 2015, Pullman, WA. http://css.wsu.edu/biofuels/ (ABSTRACT)
  • Type: Other Status: Published Year Published: 2015 Citation: 16. du Toit, L.J., Waters, T., and Reitz, S. 2015. Internal dry scale and associated bulb rots: Bane of the 2014 Pacific Northwest onion season. Onion World May/June 2015:4-7.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 17. du Toit, L.J., and Waters, T.W. Growing onion bulb crops and Allium seed crops in close proximity: IYSV risk assessment and management. Onion Session of the Pacific Northwest Vegetable Association Annual Convention & Trade Show, 18-19 Nov. 2015, Kennewick, WA. (~250 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 18. du Toit, L.J. Ignorance is bliss? History repeated for crucifer black leg in the Pacific Northwest. General Vegetable Session of the Pacific Northwest Vegetable Association Annual Convention & Trade Show, 18-19 Nov. 2015, Kennewick, WA. (~100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 20. du Toit, L.J. Ignorance is bliss? History repeated for crucifer black leg in the Pacific Northwest. Washington Tilth Producers Association Annual Meeting, 13-15 Nov. 2015, Spokane, WA. (~50 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 21. du Toit, L.J. Onion diseases in Washington State. Invited presentation at 38th Argentine Horticultural Congress, 16th National Floricultural Conf., 8th Scientific Meeting on Onion from MERCOSUR, and 3rd Regional Plant Protection and Toxicology Conf., 5-8 Oct. 2015, Bah�a Blanca, Argentina. (150 attendees). Also participated in two meetings with onion stakeholders in Lower Rio Colorado River, with a presentation at each meeting on onion bacterial bulb rots.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 22. du Toit, L.J. Ignorance is bliss? History repeated for brassica black leg in the Pacific Northwest. Presentation to Skagit Co. Commissioners, 25 Aug. 2015, Mount Vernon, WA. (5 people + presentation recording televised) http://skagit.granicus.com/MediaPlayer.php?view_id=8&clip_id=2036
  • Type: Other Status: Other Year Published: 2015 Citation: 23. du Toit, L.J. Invited by Cornell University Plant Pathology & Plant-Microbe Biology Graduate Student Association to give 2 seminars and meet with students and faculty to discuss the WSU vegetable seed pathology program. Seminar topics on Seeds Sown and Harvests Reaped: Vegetable Seed Crop Pathology in the Pacific Northwest on the Ithaca campus on 11 Mar., and Establishing a Career in Applied Plant Pathology on the Geneva campus on 12 Mar. 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 19. du Toit, L.J. Onion internal dry scale and bulb rots. Onion Session of the Pacific Northwest Vegetable Association Annual Convention & Trade Show, 18-19 Nov. 2015, Kennewick, WA. (~250 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 24. du Toit, L.J. Black leg, light leaf spot, and white leaf spot of crucifers in the Pacific Northwest: Lessons learned from the 2014 Willamette Valley epidemic. Douglas Co. and Okanogan Co. Growers Meeting. Invited to help growers avoid introducing seedborne pathogens on crucifer cover crop and canola seed. 3 Mar. 2015, Waterville, WA. (25 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 25. du Toit, L.J., Derie, M.L., Correll, J.C., and Feng, C. 2015. Phomopsis/Diaporthe and spinach seed: History, concerns, and research update. 2015 International Spinach Conference, 24-25 Feb. 2015, Yuma, AZ (also listed in abstracts). (~200 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 26. du Toit, L.J., and Derie, M.L. Suppression of Fusarium wilt in spinach seed production using compost. 2015 International Spinach Conference, 24-25 Feb. 2015, Yuma, AZ (also listed in abstracts). (~200 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 27. du Toit, L.J. Black leg of crucifers in the Pacific Northwest: Lessons learned from the 2014 Willamette Valley epidemic. Skagit Farmers Supply Growers Recertification Day, 18 Feb. 2015, Mount Vernon, WA. (~150 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 28. du Toit, L.J. Black leg in brassica crops and foliar nutrient analyses for table beet seed crops. Wilbur-Ellis Co. and Sakata America Annual Seed Growers Meeting, 3 Feb. 2015, Burlington, WA. (75 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 29. du Toit, L.J. 2014 Black leg, light leaf spot, and white leaf spot epidemic in the Willamette Valley of Oregon: Protecting Washingtons Brassica seed industry. Puget Sound Seed Growers Association Annual Meeting, 30 Jan. 2015, Mount Vernon, WA. (75 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 30. du Toit, L.J., and Derie, M.L. Table beet seed production in Washington: 2014 Disease and fertility assessments. Puget Sound Seed Growers Association Annual Meeting, 30 Jan. 2015, Mount Vernon, WA. (75 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 31. du Toit, L.J., and Correll, J. Update on Phomopsis (Diaporthe) and spinach seed. Presentation to the Emerging Disease Committee, 54th American Seed Trade Association Vegetable & Flower Conference, 24-27 January 2015, Tampa, FL (80 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 32. du Toit, L.J. Emerging Brassica diseases in the Pacific Northwest: Black leg, light leaf spot, and white leaf spot. Presentation to the Emerging Disease Issues Committee, 54th American Seed Trade Association Vegetable & Flower Conference, 24-27 January 2015, Tampa, FL (80 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 35. Myers, R., and du Toit, L.J. Keynote panel  An overview of cover cropping in the PNW  Opportunities and challenges. Presentation on the 2014 black leg epidemic in the Willamette Valley, and potential modifications to the WSDA crucifer quarantine to protect brassica oilseed crops in the irrigated and dryland areas of central and eastern Washington. 2015 PNW Oilseed & Direct Seed Conference, 20-22 Jan. 2014, Kennewick, WA. (~250 people) http://css.wsu.edu/biofuels/presentations/2015pnw-oilseed-direct-seed-conference/powerpoint-presentations/
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 36. du Toit, L.J. Allium, bean, and crucifer seed quarantines in Washington: Do the rules suffice? Columbia Basin Vegetable Seed Association Annual Meeting, 20 Jan. 2014, Moses Lake, WA. (~100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 33. du Toit, L.J., and Correll, J. Update on Phomopsis (Diaporthe) and spinach seed. Presentation to the American Seed Research Foundation Committee, 54th American Seed Trade Association Vegetable & Flower Conference, 24-27 January 2015, Tampa, FL (40 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 34. du Toit, L.J. Allium, bean, and crucifer seed quarantines in Washington: Do the rules suffice? Columbia Basin Crop Consultants Association 2015 Short Course, 21-22 Jan. 2015, Moses Lake, WA. (~150 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 37. du Toit, L.J. Iris yellow spot virus management considerations. Columbia Basin Vegetable Seed Association Annual Meeting, 20 Jan. 2014, Moses Lake, WA. (~100 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 38. du Toit, L.J. Onion internal dry scale: An emerging problem associated with climate change in the Pacific Northwest? W2008 Multi-state project annual meeting, 10 Dec. 2015, Salt Lake City, UT. (25 people)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: 39. du Toit, L.J. Ignorance is bliss? History repeated for brassica black leg in the Pacific Northwest. Brown bag lunch seminar at WSU Mount Vernon NWREC, 21 May 2015, Mount Vernon, WA. (60 people)
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: 1. Bull, C.T., Ortiz-Lytle, M.C., Ibarra, A.G., du Toit, L.J., and Reynolds, G. 2015. First report of bacterial blight of crucifers caused by Pseudomonas cannabina pv. alisalensis in Minnesota on arugula (Eruca vesicaria subsp. sativa). Plant Disease 99:415.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: 2. Christianson, C.E., Jones, S.S., and du Toit, L.J. 2015. Screening carrot germplasm for resistance to Xanthomonas hortorum pv. carotae. HortScience 50:341-350.


Progress 11/22/13 to 09/30/14

Outputs
Target Audience: Vegetable and vegetable seed growers, vegetable seed industry personnel, extension personnel, researchers, consultants, graduate and undergraduate students, postdoctorates, technical staff. Changes/Problems: Difficulties with the formulations of commercial mycorrhizal products available to growers not being compatible with the onion planting equipment limited the ability to get effective evaulation of mycorrhizal inoculations in onion growers fields in 2014. This is being discussed with growers in winter 2014-15, and a greater diversity of commercial products is being obtained to try and address this problem. Discussions are ongoing with USDA APHIS PPQ about the quarantine status of the two Phomopsis/Diaporthe species found on spinach seed to date, given that one of these species is now known to occur in olive trees in CA. This will affect the direction of the spinach Phomopsis research project in 2015. What opportunities for training and professional development has the project provided? Attendance at professional meetings for presenting results, networking with specialists on the crops/diseases, and providing graduate students, a postdoctorate, and technical staff with opportunities to present their results and learn from growers and related agricultural stakeholders. How have the results been disseminated to communities of interest? See the list of service and events noted in 'Other Products' above. Numerous presentations, workshops, field days, seminars, etc. were held throughout the year in WA, OR, AZ, Brazil, Netherlands, and South Africa. What do you plan to do during the next reporting period to accomplish the goals? Continue as planned, with modifications as described above.

Impacts
What was accomplished under these goals? CARROT SEED 1 ) A second year of screening of a subset of the USDA carrot Plant Introduction (PI) germplasm collection for resistance to Xanthomonas hortorum pv. carotae was completed by MS student, Eric Christianson. He attempted backcrossing putative resistant lines with public inbred lines from Wisconsin for release to carrot breeding programs, but most of the plants died from black rot caused by Alternaria radicina. The research thesis was completed in August 2013, and the student graduated. Results were submitted for publication in HortScience in Dec. 2014 and to the Allium and Umbelliferae newsletters. 2) Continue evaluating bactericides and cultural practices for improved management of bacterial blight in carrot seed crops in the PNW: Research collaboration has been initiated with Assistant Prof. Jeremiah Dung at the Oregon State University Madras REC on this topic. Input was provided on several grant proposals he prepared to state and federal agencies. 3) Initiate a carrot powdery mildew resistance screening project in an effort to identify new potential sources of resistance to introgress into commercial carrot cultivars: The CA Fresh Carrot Advisory Board did not fund a proposal to work on this project, so the research was not initiated. However, research is in progress with a USDA OREI grant in 4 cooperating states to evaluate selection of carrot breeding lines under organic and conventional production conditions in each state. Assistance was provided on disease evaluations in the replicated plots in each production condition in WA, including powdery mildew, Cercospora leaf spot, and bacterial blight. Samples of carrot foliage from the trials in WI, IN, and CA were received and examined. The first report of bacterial blight of carrot in Indiana was published in Plant Disease, in collaboration with an MS student, Eric Christianson. ONION SEED 1) Assess the impact of soil fumigation on mycorrhizal associations and soilborne diseases of onion in the Columbia Basin, and the potential role of mycorrhizal inoculants on alleviating adverse effects of soil fumigation, particularly for reducing the impact of soilborne diseases such as Rhizoctonia stunting and pink root: 4 conventional and 5 certified organic fields used for onion bulb crops in 2014 were surveyed for mycorrhizae by sampling soil just prior to planting, and sampling onion plants in each field at mid-bulbing. Onion seed was planted in the soil from each field to bait for mycorrhizae, and the roots stained for quantifying mycorrhizal colonization. Mycorrhizae were observed in all the fields at relatively high incidences and % colonization of the roots, which suggests that mycorrhizal populations can rebound relatively rapidly after soil fumigation with synthetic fumigants or biological fumigants (mustard cover crops). Three farms attempted to apply commercial mycorrhizal products in their onion bulb crops, but problems with compatibility of the product formulations with their planting equipment either limited what product(s) could be applied or prevented objective, fair evaluation of the products. This is being addressed for the 2015 season with additional commercial products made available to growers. A series of growth chamber trials was set up in 2014 to evaluate: 1) the effect of mycorrhizae on stunting of onions caused by Rhizoctonia solani, 2) the effects of fungicide seed treatments and soil applications on efficacy of mycorrhizae soil inoculation, 3) the effect of different levels of P in the soil on establishment of mycorrhizae in onion plants, 4) to compare two commercial mycorrhizae products for enhancing onion growth, and 5) to assess whether mycorrhizae can suppress pink root of onion caused by Phoma terrestris. One product, BioTerra Plus, significantly improved onion growth in most of the trials, until a new 'batch' of inoculum of this product was used for later trials carried out in 2014. The lack of response with this inoculum suggests either the product was not stored properly to keep the mycorrhizae viable, or there was a quality control problem with the product. Additional product has been ordered to assess this. Fungicide seed treatments commonly used by onion growers inhibited the beneficial effects of the mycorrhizae, demonstrating that growers will need to be careful about how mycorrhizae are applied to avoid negating the benefits as a result of exposure to seed treatments. Both soil applied applications of fungicides (Quadris and Fontelis) did not negate the mycorrhizal benefits in one trial, but in a repeat trial Quadris was inhibitory to mycorrhizae. The mycorrhizae were not affected by soil P levels ranging from 20 to ~50 ppm. The inoculation rate and protocol used for the pink root trials was too aggressive to assess effectively if mycorrhizae could suppress this disease. Additional inoculation protocols will be evaluated. 2) Results of research on Rhizoctonia infection in onion and pea crops were accepted for two papers submitted to Plant Disease, and published in two Plant Disease Management Reports. SPINACH SEED 1) Examine additional potential management practices for Fusarium wilt and Verticillium wilt in spinach seed crops in the maritime PNW: A large field trial evaluating a compost for suppression of Fusarium wilt in spinach seed crop was carried out in a grower's field in 2014. Results to date revealed significant suppression of Fusarium wilt, as observed in a 2013 field trial. Seed health assays are in progress for seed harvested from the trial. The same compost was also evaluated in a grower's beet seed crop to determine if compost amendment could help improve beet seed yields. Seed yield was increased by up to 20% with a single application of the compost just prior to planting (~20 tons/acre). A paper was accepted for publication in Plant Disease from a former PhD student's dissertation on Fusarium wilt, and 2 more papers are in preparation for this journal. 2) Identify spinach seed lots infested with either of the two quarantine species of Phomopsis/Diaporthe, Diaporthe viticola and D. melonis var. brevistylospora, evaluate potential organic and conventional fungicide seed treatments for treating infested lots, and assess the pathogenicity/host range of isolates of these two quarantine species on spinach and other pant species that might serve as hosts of these fungi: Multiple spinach seed lots produced in the EU were screened and cultures sent to USDA APHIS PPQ to identify lots infected specifically with the two quarantine species of this fungus. >20 million seeds were screened individually by hand. A seed lot infected with D. melonis var. brevistylospora was subjected to a range of organic and conventional seed treatments, and seed germination and health assays completed. None of the treatments entirely prevented development of the fungus on seeds after 21 days of incubation, but the most effective treatments reduced development of the pathogen to <1% incidence. The seed lot infected with D. viticola has not yet been utilized for seed treatment evaluations as a research paper was found that documents the presence of this species occurring naturally on olive trees in CA, i.e., the justification of the quarantine status of that species is being clarified with APHIS PPQ given this record of the fungus occurring in the primary region of spinach production in the USA.

Publications

  • Type: Journal Articles Status: Awaiting Publication Year Published: 2014 Citation: Bull, C.T., Ortiz-Lytle, M.C., Ibarra, A.G., du Toit, L.J., and Reynolds, G. 2015. First report of bacterial blight of crucifers caused by Pseudomonas cannabina pv. alisalensis in Minnesota on arugula (Eruca vesicaria subsp. sativa). Plant Disease 99: posted in First Look on 20 Nov. 2014. http://dx.doi.org/10.1094/PDIS-10-14-1020-PDN
  • Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Gatch, E.W., and du Toit, L.J. 2015. A soil bioassay for predicting the risk of spinach Fusarium wilt. Plant Disease 99: accepted 7 Oct. 2014. PDIS-08-14-0804-RE
  • Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Sharma-Poudyal, D., Paulitz, T.C., and du Toit, L.J. 2015. Stunted patches in onion bulb crops in Oregon and Washington: Etiology and yield loss. Plant Disease 99: accepted 10 Nov. 2014, posted in First Look on 24 Nov. 2014. http://dx.doi.org/10.1094/PDIS-05-14-0441-RE
  • Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Sharma-Poudyal, D., Paulitz, T.C., Porter, L.D., and du Toit, L.J. 2015. Characterization and pathogenicity of Rhizoctonia and Rhizoctonia-like species from pea crops in the Columbia Basin of Oregon and Washington. Plant Disease 99: accepted 25 Nov., posted in First Look on 3 Dec. 2014. http://dx.doi.org/10.1094/PDIS-08-14-0803-RE
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: du Toit, L.J., and Derie, M.L. 2014. White rust of Echinacea angustifolia and E. purpurea in North America caused by a Pustula species. Plant Disease 98:856.
  • Type: Other Status: Published Year Published: 2014 Citation: du Toit, L.J., Derie, M.L., and Waters, T.D. 2014. 2013 Carrot cavity spot Serenade Soil trial. Research report submitted to Dean Christie, Bayer CropScience, in Jan. 2014. 6 pp.
  • Type: Other Status: Published Year Published: 2014 Citation: du Toit, L.J., Derie, M.L., and Waters, T.D. 2014. 2013 Onion pink root Serenade Soil efficacy trial in Pasco, Washington. Research report submitted to Dean Christie, Bayer CropScience, in Feb. 2014. 5 pp.
  • Type: Other Status: Published Year Published: 2014 Citation: du Toit, L.J., Sharma-Poudyal, D., Knerr, J., and Paulitz, T. 2014. Mycorrhizae in onion bulb production in the Columbia Basin. Pp. 7-8 in: 2014 WSU Onion Cultivar Demonstration & Field Day handouts. Washington State University, Pullman, WA.
  • Type: Other Status: Published Year Published: 2014 Citation: du Toit, L.J., Sharma-Poudyal, D., Paulitz, T., Hamm, P., and Eggers, J. 2014. Effect of deep vs. shallow tillage on onion stunting caused by Rhizoctonia solani AG 8 and onion bulb yield. Pp. 9-10 in: 2014 WSU Onion Cultivar Demonstration & Field Day handouts. Washington State University, Pullman, WA.
  • Type: Other Status: Published Year Published: 2014 Citation: Ocamb, C.M., and du Toit, L.J. 2014. Black leg in Brassiceae crops and wild crucifers: 2014 epidemic in the Willamette Valley of Oregon. 2 pp. http://mtvernon.wsu.edu/path_team/brassicaceae.htm#blackleg and in Whatcom Ag Monthly 3:1-3.
  • Type: Other Status: Published Year Published: 2014 Citation: Pappu, H.R., Waters, T., Wohleb, C., Schroeder, B.K., and du Toit, L.J. 2014. W2008 Accomplishments for 2013 by Washington State participants. March 2013. 6 pp.
  • Type: Other Status: Published Year Published: 2014 Citation: Schroeder, B.K., du Toit, L.J., Waters, T., and Reitz, S. 2014. Tackling challenges facing Pacific Northwest onion growers. Onion World Dec. 2014:20-23.
  • Type: Websites Status: Published Year Published: 2014 Citation: website maintained and revised extensively (http://mtvernon.wsu.edu/path_team/vegpath_team.htm) on the PNW vegetable industry, images of vegetable diseases, & newsletters
  • Type: Conference Papers and Presentations Status: Other Year Published: 2014 Citation: Invited presentations at conferences and workshops: * du Toit, L.J. Neck rot in onions. Bejo Zaden Training Days  Onion and Cauliflower. 2-5 Sep. 2014, Warmenhuizen, Netherlands (~80 people). * du Toit, L.J. Detection methods for seedborne bacteria and nematodes. Advances in detection of plant pathogens in seeds and their implications, 47th Brazilian Phytopathological Mtg, 17-22 Aug. 2014, Londrina, Brazil. (~250 people) * du Toit, L.J. White mold: Sclerotonia sclerotiorum. Invited presentation for workshop Managing Sclerotinia/White Mold in the Columbia Basin, 19 Mar. 2014, Moses Lake, WA. (90 people) * du Toit, L.J. Mycorrhizae and Fusarium basal rot in onion bulb crops. Two invited presentations with onion growers in Ceres and Kouebokkeveld of Western Cape, South Africa, 11 Mar. 2014 (40 people) * du Toit, L.J. Soilborne disease management in vegetable rotations. Ceres, South Africa, 11 Mar. 2014. (10 people) * du Toit, L.J. Black rot and white mold in brassica vegetable seed crops. Syngenta Seeds in Western Cape, South Africa, 10 Mar. 2014. (30 people) * du Toit, L.J., and Price Youngquist, C. Biosolids compost use in vegetable seed crops, potatoes, and small grains. Soil Quality Network 2014, 13 Feb. 2014, Mount Vernon, WA. (~100 people) * du Toit, L.J., and Lew-Smith, J. Managing seedborne diseases in seed production. 7th Organic Seed Growers Conf, 30 Jan.  2 Feb. 2014, Corvallis, OR. (~65 people) Webinar recorded presentation: http://bit.ly/1iXoUbO * du Toit, L.J. Diagnosing diseases in the field. Annual Basin Producers 2014 Pesticide Recertification Day, 17 Jan. 2014, Moses Lake, WA. (~200 people) * du Toit, L.J. Does this product really work? Distinguishing sound science from hot air in product promotional materials. Columbia Basin Crop Consultants Assoc 2014 Short Course, 15-16 Jan. 2014, Moses Lake, WA. (~80 people) * du Toit, L.J. Management of Botrytis in onion; and vascular wilts, leaf spots, and Phomopsis, a quarantine fungus, in spinach. Bejo Seeds, Inc. Bejo Seeds, Inc., 13 Jan. 2014, Mount Vernon, WA. (~25) * Collins, B.D., du Toit, L.J., Westerveld, S.M., and McDonald, M.R. Suppression of Fusarium wilt of spinach with chemical and biological fumigants. VIII Internat Symposium on Chemical & Non-Chemical Soil & Substrate Disinfestation. 13-18 July 2014, Turin, Italy. Poster. * du Toit, L.J. Management of Fusarium and Verticillium wilts in spinach seed production: Research update. Puget Sound Seed Growers Assoc Annual Mtg, 20 Feb. 2014, Mount Vernon, WA. (~50 people) * du Toit, L.J. Phomopsis and spinach seed: Progress report.
  • Type: Other Status: Other Year Published: 2014 Citation: Workshops, field days, tours, and outreach: * 2014 WSU Onion Field Day, Carr Farms, Pasco, WA, 28 Aug. 2014. (~100 people) * 2014 WSU Extension Carrot Field Day, 15 Aug. 2014, Pasco, WA. Presented carrot disease management summary. (~30 people) * 2014 Washington Pest Control Tour of WA State Commission on Pesticide Registration in central WA, 28-31 July 2014. ~60 legislators or staff, industry reps, WA State Depts. of Agriculture, Ecology, and Labor & Industries; WSU administrators, National Marine Fisheries Service, US Environmental Protection Agency, etc. * WSU Mount Vernon NWREC Field Day. ~100 growers, consultants, extension educators, researchers, WSDA and seed industry personnel. 11 Jul. 2014, Mount Vernon, WA. * WSU Vegetable Seed Field Day. ~40 vegetable personnel. 20 Jun. 2014, Skagit Valley, WA. * Emergency meeting Plant Disease Alert Meeting: Black Leg & Leaf Spots in Brassica, Mustard, & Radish Crops following widespread epidemic of black leg and two leaf spot diseases, white leaf spot and light leaf spot, in brassica crops in Willamette Valley in 2014. 18 Jun. 2014, Albany, OR. * Western WA Small-Seed Advisory Comm (2 Jun 2014) and Columbia Basin Vegetable Seed Field Reps Assoc (3 June 2014): 1) epidemic of black leg of brassicas (caused by Phoma lingam) in Willamette Valley OR in 2014, a quarantine disease in northwestern WA; and 2) finding white rot in an onion seed crop (Sclerotium cepivorum) in Grant Co. in 2014, a 4-co. quarantine area of WA for this disease. With C. Ocamb, prepared 2-page Alert on black leg for distribution among brassica growers, seed dealers, seed companies in PNW. Organized discussions and research/extension planning on beet seed crop production in western WA in response to declining yields: 31 Jan. (30 people), 23 Apr. (40 people), 8 Jul. (invited Prof. Irwin Goldman, table beet breeder and Chair of Dept. of Horticulture, Univ of Wisconsin; 25 people). * 3-h discussion on disease management in onion seed crops for JW Seeds, 13 Mar. 2014, Oudtshoorn, South Africa. * 4-h workshop on disease and insect management in onion seed crops with Klein Karoo Seed Production, 12 Mar. 2014, Oudtshoorn, South Africa. * Led discussion on management of soilborne diseases of vegetables for mixed vegetable farms in Western Cape, South Africa, 11 Mar. 2014. * WSU Onion Cultivar Storage Demonstration Trial, Hartley Farms, Benton City, WA, 6 Feb. 2014. * Sustainability of Organic Spinach. Invited seed pathology expertise for spinach growers, crop consultants, and seed industry reps (~65 people) in Yuma, AZ and Salinas, CA, 8 Jan. 2014. * Gave tours of WSU Mount Vernon NWREC and/or vegetable seed crops in northwestern or central WA, and discussed vegetable seed production and seed pathology: WSU CAHNRS deans, directors, and department chairs (20 Oct.); owner of Bejo Zaden, Holland (25 Jul.); HygroTech Seed Co., South Africa (6 Aug.); Gates Foundation (5 Nov.); and other groups.