Progress 09/01/11 to 08/31/16
Outputs
Target Audience:Our target audience was the US and global basil industry including commercial field and greenhouse growers, culinary herb buyers and distributors, processors (fresh frozen, freeze-dried), seed companies and gardeners that all were impacted by the downy mildew disease and those that had problems controlling fusarium disease. We focused our efforts in two critically needed areas. First, the development of improved sweet basil varieties with resistance to Downy mildew, as well as fusarium wilt disease, with to improve the tolerance to chilling injury. Each of which are causing significant crop and economic losses to US growers. The second area was to develop strategies for disease management including seed assays, disease monitoring and disease forecasting system, as well identifying an array of organic and conventional fungicides that can mitigate against the onset and spread of downy mildew. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The National Basil Downy Mildew Monitoring Program was established by McGrath from this project and continues today. Growers, gardeners, extension specialists, scientists, media, and people with gardening web pages were provided information about basil downy mildew through presentation, articles, reports, and responses to e-mail and telephone inquiries. The weekly newsletter for Long Island growers was used to provide them information on the status of basil downy mildew in the area plus nearby locations (mid-Atlantic region) that could be a source of wind-dispersed spores. This project provided the opportunity for graduate student training. At Rutgers, we had 1 MS graduate student (Female) in the evaluation of fungicides for controlling basil downy mildew, and she is now pursuing her Ph.D. studies also on sweet basil fusarium resistance, and 1 Ph.D. (male) in genetics and breeding of downy mildew resistant basil. At Florida and UMass training opportunities for one postdoc in each place were provided. Many undergraduate students and additional graduate students volunteered and/or became engaged in specific parts of this research which provided training in genetics, breeding, horticultural production, tissue culture and micropropagation, analysis of the aroma and flavor of basils and in human sensory responses to different chemotypes of basil. Growers received trainings in disease control strategies with basil. How have the results been disseminated to communities of interest?Results have been disseminated using a variety of approaches for the different communities of interest and over each year of the project. Commercial growers, buyers, processors, dealers/traders and seed company's were engaged throughout the entire project through annual meetings, and workshops, summer field days in FL, NJ and NY, specialized trainings in control strategies against downy mildew (options for conventional and organic growers), use of field demonstrations (relative to fungicide applications and other agricultural chemicals and organic products to identify those that work effectively and ways to maximize their efficacy against downy mildew; and annual field tests in developing genetic resistant sweet basil lines to get consumer, grower and buyer feedback on the new disease resistant sweet basils production and yield performance, and market acceptance). Use of twilight and other extension opportunities were used to disseminate information in DM identification and control to home gardeners and those in the agri-business. Additional, participation in national, regional and statewide meetings was conducted to reach scientific and grower audiences. Importantly applied research studies were completed that allowed for the registration of new chemical control agents that commercial growers that are able to use. In FL, NJ and NY field and greenhouse trials were conducted as trainings and demonstrations for commercial growers, seed companies, and the public. Extensive evaluations of fungicides and organic products to control DM in FL, NJ and NY showed that high level of control can be obtained with conventional fungicides applied on a preventive, weekly schedule. In contrast, managing downy mildew with an organic fungicide program remains quite difficult. Experience gained through working on this project has been used to conduct additional evaluations of fungicides. This work is being supported by industry and by the IR-4 program. Some examples include: Presentations at scientific meetings Pyne, R., Honig, J., Vaiciunas, J., Bonos, S., Wyenandt, A. and Simon, J. A First Genetic Map of Sweet Basil (Ocimum basilicum) Facilitated by Double Digestion Restriction Site Associated DNA Sequencing (ddRADseq). National Association of Plant Breeders (NAPB) National Meeting. August 15-17, 2016, Raleigh, NC. Oral Presentation. Pyne, R., Koroch, A., Juliani, R. and Simon, J. Essential Oil Extraction Methods and Inheritance of Major Volatiles in Sweet Basil (Ocimum basilicum). 7 th Annual Conference American Council for Medicinally Active Plants (ACMAP) June 29 - July 1, 2016 Lima, Peru. Poster. McGrath, M. T. 2016. Engaging the public to report occurrence of a new disease, basil downy mildew. (poster presented at APS meeting in Aug; selected for inclusion in a poster huddle on "What types of research should be prioritized when new diseases are found?"). Phytopathology 105:S4.92. Allen, K.S., Guo, L., Ma, L.J., Wick, R.L. (2016) Identification of candidate genes for study of the sweet basil host response to infection by Peronospora belbahrii.Postersessionpresentedat: Northeastern Plant, Pest, and Soils Conference; 2016 Jan 3-7; Philadelphia, PA. Pyne, R., Honig, J., Vaiciunas, J., and Simon, J. Genetic Relationships Between Basil (Ocimum spp.) Germplasm Provide Insights for Downy Mildew Resistance Breeding. American Society for Horticultural Science (ASHS) 112th Annual Conference. July 28-31, 2015. New Orleans, Louisiana. Oral Presentation. Koroch, A., Pyne, R., Curry, T. and Simon, J. Detection and Elimination of Tobacco Streak Virus in Basil (Ocimum spp). ACMAP 5th annual Conference. June 9-12, 2015. Washington State University, Spokane, WA. Poster. Pyne, R., Koroch, A., Simon, J. and Wyenandt, C. Inheritance of resistance to basil downy mildew (Peronospora belbahrii). ASHS. 111th Annual Conference. July 28-31, 2014. Orlando, Florida. HortScience 49(9):245. Oral Presentation. Extension Presentations Pyne, R. and Simon, J.E. Basil Breeding Program - Where Are We with Downy Mildew? In: NJ Twilight Meeting. September, 2016. The Snyder Research and Extension Farm, Pittstown, NJ. September 9, 2014 & Rutgers Agricultural Research and Education Center, Bridgeton, NJ. Pyne, R. Wyenandt, A., Koroch, A., and Simon J. Breeding for Resistance to Basil Downy Mildew: Where are we now? In: New Jersey Agricultural Convention: USDA-SCRI Basil Downy Mildew Workshop. February 5, 2015. Atlantic City, NJ. McGrath, M. T. Information Gained about Vegetable Diseases from Recent Research and Observations on Organic Farms. 2015 Long Island Agricultural Forum. Sustainable Ag Session. Speonk, NY. 1/8/15. McGrath, M. T Plant Disease Management in Organic Systems. Virginia Association for Biological Farming Conference. Richmond, VA. 1/30/15. McGrath, M. T Downy Mildew and Its Occurrence Across the USA. 2015 NJ Agricultural Convention and Trade Show. In Basil Downy Mildew Workshop. Atlantic City, NJ. 2/5/15. McGrath, M. T Efficacy of Conventional and Organic Fungicides for Managing Basil Downy Mildew, Long Island. 2015 NJ Agricultural Convention and Trade Show. In Basil Downy Mildew Workshop. Atlantic City, NJ. 2/5/15. McGrath, M. T Managing Basil Downy Mildew Organically Can Be Done Based on Research Results. 2016 Long Island Agricultural Forum. Sustainable Ag Session. Speonk, NY. 1/14/16. McGrath, M. T Occurrence and Impact of Downy Mildew on Sweet Basil in 2015. 2016 NJ Agricultural Convention and Trade Show. Basil Workshop. Atlantic City, NJ. 2/11/16. McGrath, M. T Managing Basil Downy Mildew - New York Perspective. 2016 NJ Agricultural Convention and Trade Show. Basil Workshop. Atlantic City, NJ. 2/11/16. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Our national consortium was formed to address the devastating crop losses that US growers experienced by the arrival into the US of downy mildew (DM, Peronospora belbahrii) first reported in Florida in 2007, for which then and still today there are no commercial genetic resistance available in acceptable sweet basils. Thus, this project focused on (1) improving management techniques to mitigate disease severity from DM and fusarium (FOB) and (2) developing sweet basil breeding lines with reasonable levels of DM resistance. As a direct result of this project from extensive study of chemical controls several new products have now been labeled nationally for growers to use with additional registrations in the pipeline (Wyenandt et al 2015). Although chemical controls show promise under low disease pressure, only partial relief to growers is provided under high inoculum levels and at a significant economic and environmental cost. Furthermore, no organic controls were found to be effective leaving all those involved in certified organic production without options (Wyenandt et al 2015). Other collaborative partners found that environmental manipulation (temperature and light quality) can suppress DM sporulation (Patel et al. 2016) in greenhouse production. Leaf curvature and stomatal density and length affect downy mildew development and sporulation. Considerations of these leaf morphological characteristics were found to be useful phenotypic traits in breeding for downy mildew resistance in Ocimum (Homa et al. 2016). Over the past five years high-throughput downy mildew response evaluation of > 200 basil accessions and phylogenetic analysis of >170 basil accessions has been critical in building this foundation (Wyenandt et al. 2010) and a program for effective DM resistance breeding (Pyne et al. 2014a, 2014b, 2015). After identifying several sources of resistance to DM among non-sweet basil phenotypes from greenhouse screening (Pyne et al. 2014), we selected one that was most closely related to commercial O. basilicum accessions. A six-generation, full-sibling family developed from a cross between that resistant line and a sweet basil FOB tolerant Rutgers inbred breeding line SB22 demonstrated DM resistance as being under two-gene control (Pyne et al. 2015). The F2 generation was subsequently genotyped using >1,800 bi-allelic SNPs generated by double digestion restriction site associated DNA sequencing (ddRADseq) to create what will be the first genetic map publically available for sweet basil (data not presented). Recent quantitative trait loci (QTL) analysis detected 2 major genomic regions, which control DM resistance in the MRI x SB22 F2 mapping population based on phenotyping in two locations. We have been using a pedigree selection method to develop advanced breeding material that are now stable for DM resistance as well as flavor, leaf shape, biomass and other essential traits necessary for commercial marketability. We have developed a model for highly effective breeding of sweet basil that can now be easily adopted for qualitative traits (i.e., FOB) and potentially quantitative traits (i.e., chilling tolerance). Screening for polymorphic EST and scoring progeny for mapping: We have screened 240 EST-SSR markers for functionality for polymorphism among our F2 mapping population parents. We identified 149 functional EST-SSR markers, 49 of which were polymorphic and 42 of which have now been mapped to 23 of 26 linkage groups in our ddRADseq linkage map which contains >1,880 SNPs. In addition, we have identified a major QTL dm11.1 with strong association to downy mildew resistance across three location x year environments. Through additional screening we also developed a core set of 20 EST-SSR markers that consistently amplify across Ocimum spp. Using this set we have screened 179 accessions of basil in order to conduct population structure/clustering and genetic diversity analysis. Each accession genotyped has also been evaluated for response to basil downy mildew in the field, greenhouse or both. Combined genotype and phenotype data demonstrates how genetically diverse identified DM resistant accessions are in comparison to commercial sweet basil. This information is increasing the precision and efficacy of our crossing schemes/breeding programs. Using another approach, an analysis pipeline that integrates several bioinformatic software tools to enable rapid gene discovery and expression analysis of a plant host and its obligate parasite simultaneously by sequencing mixed host and pathogen transcripts using next generation sequencing techniques was developed by our UMass Team members. This led to de novo-assembly based data analysis pipeline for plant obligate parasite metatranscriptomic study with sweet basil and the DM parasite (each lacking a sequenced genome) candidate host defense genes and pathogen virulence genes that are highly expressed during infection were identified (Guo et al. 2016). Analyze plants for aromatic compounds: We have analyzed essential oil composition for all major accessions with which we are currently working in our breeding program. This includes parents, inter-/intraspecific hybrids and our F2 mapping population. We use results for direction of appropriate breeding strategies as well as determination of gene action and basic QTL mapping studies. Among interspecific F1 hybrids, volatile data indicates that DM resistant non- O. basilicum species will confer their major essential oil components with dominant gene effects, creating a phenotypic challenge to breeding commercial aroma/flavor into DM resistant basil. We have begun to develop near isogenic lines (NILs) from these exotic species, which contain small genomic regions of the donor (exotic) species genomes in sweet basil backgrounds. Screen chilling tolerant OP and hybrids for chilling and Fusarium: We evaluated a number of previously developed chilling tolerant breeding lines under 4°C for 72 hrs. (corresponding to the typical conditions for shipping). Initial results demonstrated heterogeneity among individuals potentially due to open pollinated breeding. Five generations of recurrent selection have stabilized these breeding lines for chilling tolerance (showing little damage after screening). In parallel we have developed breeding lines with intermediate resistance to Fusarium wilt and are currently developing NILs that will have 'true' resistance introgressed from a unique sweet basil line we identified. We have hybridized Fusarium wilt resistant material with chilling tolerant material and now enter the F2 generation for selection chilling/FOB tolerance.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
2016. Homa, K., W.P. Barney, D. Ward, C.A. Wyendant and J.E. Simon. Morphological characteristics and susceptibility of basil species and varieties to Peronospora belbahrii. HortScience: 51(11):1389-1396.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Patel, J., Zhang, S. and McGrath, M. 2016. Red Light Increases Suppression of Downy Mildew in Basil by Chemical and Organic Products. J. of Phytopathology. doi: 10.1111/jph.12523
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Guo, L., Allen, K., Deiulio, G., Zhang , Y., Madeiras, A., Wick, R., and Ma, L. 2016. A De Novo-Assembly Based Data Analysis Pipeline for Plant Obligate Parasite Metatranscriptomic Studies. Frontiers in Plant Sci. July, 2016, Vol. 7, Article 925.http://dx.doi.org/10.3389/fpls.2016.00925
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
McGrath, M. T. and LaMarsh, K. A. 2015. Assessment of downy mildew susceptibility in basil cultivars and experimental resistant hybrids, 2014. Plant Disease Management Reports 9:V023.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
EVALUATING FUNGICIDE EFFICACY, PLANT VARIETAL RESISTANCE AND LEAF MORPHOLOGY IN 2013. Hama, K. DEVELOPING CONTROL STRATEGIES FOR BASIL DOWNY MILDEW (PERONOSPORA BELBAHRII), MS. School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey. 225 pp.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
McGrath, M. T. and LaMarsh, K. A. 2015. Evaluation of organic and conventional fungicide programs for downy mildew in basil, 2014. Plant Disease Management Reports 9:V026.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
McGrath, M. T., LaMarsh, K. A., Simon, J., Pyne, R. M., and Wyenandt, C. A. 2015. Assessment of downy mildew resistance in basil breeding lines and experimental hybrids, 2014. Plant Disease Management Reports 9:V027.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
McGrath, M. T. 2016. Evaluation of biopesticides for downy mildew in sweet basil, 2015. Plant Disease Management Reports 10:V034.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
McGrath, M. T. 2016. Evaluation of fungicides for downy mildew in sweet basil, 2015. Plant Disease Management Reports 10:V039.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
McGrath, M. T. 2016. Evaluation of organic and conventional fungicide programs for downy mildew in sweet basil, 2015. Plant Disease Management Reports 10:V033.
- Type:
Other
Status:
Published
Year Published:
2015
Citation:
Expect and Prepare for Downy Mildew in Basil. Up-dated this article posted at:
http://vegetablemdonline.ppath.cornell.edu/NewsArticles/BasilDowny.html
- Type:
Other
Status:
Published
Year Published:
2015
Citation:
Managing Basil Downy Mildew in the Greenhouse. April 2015 Suffolk Ag News. Vol 99. No. 4. p 10-12.
|
Progress 09/01/14 to 08/31/15
Outputs
Target Audience:Target audience were researchers, commercial basil growers and supportive allied agricultural industries including buyers, marketers, seed companies and others. Changes/Problems:There has been difficulty in procuring detailed grower survey repsonses relative to theeconomic impact that both basil downy mildew and fusarium have caused. What opportunities for training and professional development has the project provided?Field days with growers to ensure proper identifcation of the diseases and new resistant basils. Presentations and workshops including a 2-all day workshopwith growers and seed industry on our latest research with our consortium partners at University of Florida, University of Massachusetts and Rutgers University providing specific research findings and newest extension recommendations. In addition, this project has provide training opportunities to undergraduates and graduate students. How have the results been disseminated to communities of interest?Via the publication of research papers, internet, and via field days and workshops. What do you plan to do during the next reporting period to accomplish the goals?Focus on the genetics of basil downy mildew resistance, fusarium resistance and chilling tolerance. Mapping of QTLs in the F2 population potentially linked to genes involved in downy mildew resistance.Understanding the molecular basis of host resistance and pathogen virulence at the host-pathogen interface will help shed light on effective disease management for downy mildew disease. ?
Impacts
What was accomplished under these goals?
Relative to using control agents in managing basil downy mildew:During the summers of 2010-2014at the Rutgers Agricultural Research and Extension Center (RAREC) in Bridgeton, NJ, a number of conventional and biological fungicides were evaluated for efficacy in field trials. Our studies over the past 4 years have shown that foliar applications of phosphite products (FRAC code 33) such as K-Phite, Rampart, or Pro-Phyt provide the best season-long control if initiated before the pathogen appears in the region and/or prior to the onset of symptoms. In each year of the study none of the organic fungicides evaluated provided an adequate level of season-long control of basil downy mildew. Results of all trials at RAREC will be discussed in detail.Growers should know the symptoms of basil downy mildew and monitor the field daily. If the pathogen is detected in the region, growers should make frequent protectant fungicide applications before the pathogen enters the field and before symptoms appear. Relative to Developing Fusarium resistant basil:This past year we have been culturing virulent lines of fusarium (FOB), have worked out techniques to screen basil and have begun to refocus our efforts in breeding sweet basil for fusarium resistance.Screenings for genetic resistance to Fusarium wilt for introgression into sweet basil (Ocimum basilicum) were conducted during the 2015 season. In one screening, a number of Rutgers chilling tolerant lines and Fusarium resistant lines were inoculated with virulent isolate Rutgers 318 (Fusarium oxysporum f. sp. basilici). Results were encouraging for a number of sweet basil chilling tolerant lines and Fusarium resistant lines. In another study, we crossed a fusarium resistant sweet basil with one of our Rutgers sweet basil breeding lines. The F2 population was then inoculated with virulent isolates Rutgers 318 (Fusarium oxysporum f. sp. basilici) and NJSN1 (Fusarium oxysporum f. sp. basilici). Of the population screened, only a few plants were susceptible, showing that resistance can be developed from this cross. These preliminary results can aid in the design of appropriate breeding and selection strategies for the development of new FOB resistance in sweet basil and incorporation of FOB resistance into the BDM resistant sweet basil both which are currently being developed. Breeding for Basil Downy Mildew Resistance (BDM):We crossed a BDMresistant basil with a Rutgers susceptible sweet basil inbred line (SB22) to generate a full-sibling family. To determine the mode of inheritance for resistance to downy mildew in basil, six related generations of the the resistant x sensitivefamily were evaluated using a Disease severity index (DSI) at northern and southern New Jersey locations over 2 years. Segregation ratios in the F2 and backcross to the susceptible parent (BCP1) generations demonstrated chi-square goodness of fit to the two gene complementary (F2 P =0.11; BC1P1 P=0.04) and recessive epistatic (F2 P=0.03; BC1P1 P=0.63) models. Further analyses of gene effects using a weighted six-parameter scaling test provided evidence that nonallelic additive x additive and additive x dominant gene effects were highly significant (P<0.001) and resistance-reducing. All siblings in the F1 and BC1P2 generations were resistant (0.33>DSI) providing strong evidence that inheritance of resistance from the resistant basil parent was conferred by dominant alleles. This is the first report of heritable genetic resistance that can be introduced to sweet basil without the issue of sterility barriers. During this time frame we have developed a wide range of inbred lines of varying phenotypes from the most important sweet basil to new BDM resistant ornamental basils.
Publications
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2015
Citation:
Homa, K., W.P. Barney, D. Ward, C.A. Wyendant and J.E. Simon. Morphological characteristics and susceptibility of basil sepcies and varieties to Peronospora belbahrii. HortScience: (accepted).
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Pyne, R.M., A.R. Koroch, C.A. Wyenandt and J.E. Simon. 2015. Inheritance of Resistance to Downy Mildew in Sweet Basil. J. American Society for Horticultural Science 140(5):396-403.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Wyenandt, C.A., J.E. Simon, R.M. Pyne, K. Homa, M.T. McGrath, S. Zhang, R.N. Raid, L.J. Ma, R.Wick, L. Guo, and A. Madeiras. Basil downy mildew (Peronospora belbahrii): Discoveries and challenges relative to its control. Phytopathology 105:885-894.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Patel, J.S., M.L. Costa de Novaes, S. Zhang. 2015. Evaluation of the new compound oxathiapiprolin for control of downy mildew in basil. Plant Health Research 16(4):165-172.
- Type:
Other
Status:
Published
Year Published:
2015
Citation:
Raid, R. (University of Florida). Evaluation of foliar fungicides in combination with Ridomil Gold seedling drench application for management of downy mildew on sweet basil, Spring 2015.
Plant Disease Management Reports No. 9:V116.
- Type:
Other
Status:
Published
Year Published:
2015
Citation:
Raid, R. (University of Florida). Evaluation of foliar fungicides in combination with Orondis seedling drench application for management of downy mildew on sweet basil, Spring 2015.
Plant Disease Management Reports No. 9:V115
|
Progress 09/01/13 to 08/31/14
Outputs
Target Audience: We had four targeted audiences to whom our work is being addressed and who are receiving information from the researchers involved in this program. The first are the commercial growers; the second are the home gardeners, the third are those from the commercial private sector serving to support the commercial growers (e.g. seed companies, those involved in developing chemical and organic controls for basil downy mildews, and buyers for fresh sweet basil); the fourth are other researchers and scientists including plant breeders and those plant pathologists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? In each state (Florida, Massachusetts, New Jersey), field trials were conducted as training and demonstrations for commercial growers, seed companies and the public. Trainings in basil downy mildew identification and control were provided during these public field days and twilight tours. In addition, a 2-day meeting was held in Homestead, Florida with researchers from Rutgers, UMass, UFlorida and Cornell and members of the private sector representing seed companies, commercial growers in field and greenhouse. There the latest research findings of this program were shared, the current state of knowledge strategies forward discussed. Monitoring program. The National Basil Downy Mildew Monitoring Program established by McGrath (Cornell) in 2009 continued in 2014. Growers, gardeners, extension specialists, media, and scientists were provided information about basil downy mildew through presentation, articles, reports, and responses to e-mail and telephone inquiries. The weekly newsletter for Long Island growers was used to provide them information on the status of basil downy mildew in the area plus nearby locations (mid-Atlantic region) that could be a source of wind-dispersed spores. Each year a spreadsheet accessible by anyone has been set-up in Google Docs, See: (http://vegetablemdonline.ppath.cornell.edu/NewsArticles/BasilDowny.html) which was updated in 2014. Growers and gardeners making reports often included information about the occurrence and management experience, all adding to knowledge about this new disease. Those reporting are asked to include their e-mail address. As part of the SCRI project, everyone reporting has been contacted to obtain more information, in particular whether downy mildew may have occurred on basil at the location in previous years, and to provide assistance with diagnosis to confirm the report. Some additional occurrences have been learned about from primarily growers and also some gardeners who sent an e-mail after finding the above web site. The monitoring program has resulted in samples being obtained for project investigators R. L. Wick and S. Zhang for investigation of biodiversity in the pathogen. 2014 was the most important year to date for basil downy mildew in the USA. There were occurrences in greenhouses in early spring before there was outdoor production nearby, suggesting contaminated seed was the source. Affected plants were found at several retail garden centers in the northeastern USA and as far south as TN. They were at local and large chain stores, produced in small and large-scale operations. Basil plants with downy mildew were also sold to the public in Canada. Substantially more reports were logged in 2014 than in previous years: 282 to date compared to 49, 63, 63, 75, and 64 reports in 2009, 2010, 2011, 2012, and 2013, respectively. Reports came from 37 states and the District of Columbia in 2014, compared to 20, 26, 22, 26, and 21 states in the previous years. Conditions appeared to be more favorable for basil downy mildew than usual in NC, VA, DC, and MD based on 58 reports being logged from these areas and several reporters commenting they had not seen the disease before and temperatures were not as hot as typical during the summer. Reports of basil downy mildew were obtained for the first time from IA, NE, and NV. Since 2008 this new disease has been reported in 44 states plus the District of Columbia. There have been no reports from ID, NM, OK, SD, UT, and WY. Reports were also logged from Argentina, Grand Cayman, South Korea, and South Africa (all first reports from these countries at the monitoring site), as well as Mexico. Knowing that the first known occurrence of basil downy mildew was in Africa (Uganda in 1933), a search was done to find a scientist in South Africa with knowledge about the occurrence of this disease there. A professor at the African Centre for Crop Improvement responded that he had provided advice in mid-1990s to a farmer with severe downy mildew on basil being grown for export to Switzerland. This could be how the pathogen got to Switzerland, where it was first reported in 2001. How have the results been disseminated to communities of interest? In each state (Florida, Massachusetts, New Jersey), field trials were conducted as training and demonstrations for commercial growers, seed companies and the public. Trainings in basil downy mildew identification and control were provided also in winter grower schools and summer field days, twilight meetings. Some examples follow (presentations at public and scientific meetings): · Homa, K., Pyne, R., Wyenandt, A., Simon, J.E., Koroch, A.R. (2013). Evaluation for fungicides for the control of basil downy mildew; Genetics of basil breeding for resistance and tolerance to downy mildew, chilling injury and fusarium wilt. In: Basil Downy Mildew Workshop hosted by UFL. Homestead, FL. · Pyne, R. and Simon, J.E. (2014) Basil Breeding Program - Where Are We with Downy Mildew. In: NJ Twilight Meeting. 2014. The Snyder Research and Extension Farm, Pittstown, NJ. September 9, 2014. · Pyne, R. and Simon, J.E. (2014) Basil Tasting. In: Great Tomato Tasting Event. 2014. The Snyder Research and Extension Farm, Pittstown, NJ. August 27, 2014. · Pyne, R. and Simon, J.E. (2014) Rutgers downy mildew tolerant basil breeding lines. In: NJ Twilight Meeting. 2014. Rutgers Agricultural Research and Education Center, Bridgeton, NJ. August 21, 2014. · Homa, K., Pyne, R., Simon, J.E., Wyenandt, A., Barney, W.P. (2014). Evaluating fungicides for the control of basil downy mildew; Breeding for resistance to basil downy mildew.In: NJ Vegetable Growers Meeting,Atlantic City, NJ. · Pyne, R., H. Rodolfo Juliani, Adolfina R. Koroch, and James E. Simon ACMAP (American Council for Medicinally Active Plants). 2014, Assessment of essential oil composition in downy mildew resistant basils (Ocimum basilicum L.). 5th annual Conference. June 15-18, 2014. North Dakota State University. Fargo, North Dakota. (Poster) · Pyne, R., Andrew Wyenandt, Adolfina Koroch, James E. Simon and ASHS (American Society for Horticultural Science). 2014. Inheritance of resistance to basil downy mildew (Peronspora belbahrii). Annual Conference. July 31, 2014 Orlando, Florida. (Oral Presentation) · McAvoy, G., Raid, R. N., and Miller, C. 2014. Basil downy mildew: Present and future prospects for control. Southeast Regional Fruit and Vegetable Conference, Savannah, GA, January 9-14, 2014. (Poster). · Mersha, Z. and S. Zhang. 2013. Evaluation of systemic acquired resistance inducers for control of basil downy mildew. Basil Workshop, Homestead, FL. December 19-20. (Poster) · Miller, C., Raid, R. N., and G. McAvoy. 2014. Basil downy mildew: Present and future prospects for control. Annual Meeting of the Florida State Horticultural Society, Clearwater Beach, FL, June 1-3, 2014. (Poster). · Miller, C., McAvoy, G., and Raid, R. N. 2014. Basil downy mildew: Present and future prospects for control. National Association of County Agricultural Agents, Mobile, AL, July 20-24, 2014. (Poster). · Patel, J. S., S. Zhang, and M. I. Costa de Novaes. 2014. Oxathiapiprolin: An effective new chemistry for control of downy mildew of basil. APS-CPS Joint Meeting, Minneapolis, MN. August 9-13. (Poster) · Patel, J. S., M. I. Costa de Novaes, and S. Zhang. 2013. Evaluation of oxathiapiprolin to manage downy mildew of basil caused by Peronospora belbahrii. Basil Workshop, Homestead, FL. December 19-20. (Poster) · Raid, R. N. and McGrath, M. T. 2013. Evaluation of six sweet basil varieties for resistance to downy mildew. SCRI Basil Downy Mildew Workshop, Homestead, FL, December 19, 2013. (Poster) · Raid, R. N. 2013. Basil downy mildew: Present and future prospects for control. SCRI Basil Downy Mildew Workshop, Homestead, FL, December 19, 2013. (Poster). · Raid, R. N., and Zhang, S. 2013. Effects of soil drench treatments for management of basil downy mildew. SCRI Basil Downy Mildew Workshop. Homestead, FL, Dec. 19, 2013. (Oral Presentation). · Raid, R. N. 2013. Summary of basil field trials conducted for management of downy mildew in Florida. SCRI Basil Downy Mildew Workshop. Homestead, FL, Dec. 19, 2013. (Oral Presentation). · Raid, R. N. 2013. Seed-borne diseases of vegetables in Florida. Annual Meeting of the Florida Seed Association, Homasassa Springs, FL, June 2013. (Oral Presentation). · Raid, R. N. 2013. Emerging fungal threats to leafy greens and herbs in Florida. Biennial Meeting of the Florida Phytopathological Society, Ft. Lauderdale, June 6-8, 2013. (Oral Presentation). · Raid, R. N. 2013. Fungicidal management of downy mildew on multiple vegetable crops in Florida. Biennial Meeting of the Florida Phytopathological Society, Ft. Lauderdale, June 6-8, 2013. (Oral Presentation). · Patel, J. S., S. Zhang, and M. I. Costa de Novaes. 2014. Oxathiapiprolin: An effective new chemistry for control of downy mildew of basil. APS-CPS Joint Meeting, Minneapolis, MN. http://www.apsnet.org/meetings/Documents/2014_meeting_abstracts/aps2014abP189.htm · Fan, X. and S. Zhang. 2014. 2013 Basil Workshop held in Homestead of Miami-Dade County. (online) Extension Connextion Newsletter, Volume 4, Issue 1, Pages 6-7. Miami-Dade County Extension, Homestead, FL. http://miami-dade.ifas.ufl.edu/documents/ExtensionConnextion_Summer14.pdf. · Fan, X. and S. Zhang. 2014. Basil workshop held at UF TREC in Homestead, Florida. (online) Vegetarian Newsletter, Issue No. 592. Horticultural Science Department, University of Florida, IFAS. http://hos.ufl.edu/newsletters/vegetarian/issue-no-592. · McGrath, M. Basil downy mildew. In Herb Session. 2014 Mid-Atlantic Fruit and Vegetable Convention. Hershey, PA. 1/28/14. · McGrath, M. Disease Diagnosis and Management in the Home Vegetable Garden. Master Gardener Training Program. Great River, NY. 4/1/14. · McGrath, M. Disease Issues on Organic Farms: The Mildews. NOFA-NY Intensive Workshop on Organic Disease Management Strategies in (Another) Wet Year. Geneva, NY. 10/21/14. · McGrath, M. Extension articles on basil downy mildew: Expect and Prepare for Downy Mildew in Basil. Up-dated this article posted http://vegetablemdonline.ppath.cornell.edu/NewsArticles/BasilDowny.html · Wick, R.L. and M. Bess Dicklow, Basil Downy Mildew, http://extension.umass.edu/vegetable/print/536 What do you plan to do during the next reporting period to accomplish the goals? We plan to continue to focus on the genetics and breeding of DM resistant basil, to understand the mode of inheritance, essential oil and aroma profiling, to merge and breed chilling tolerance, fusarium resistance into DM resistant basils and to develop the inbred lines further for release in the creation of the hybrids. We plan to conduct our F4 and F5 progeny line studies, deveop apical stem tip meristem procedures to ensure virus-free breeding materials and to continue to explore strategies to mitigate and reduce DM injury and occurance using conventional and organic control agents. Particular attention will be given to economic impact of the DM disease, diallel crosses, backcrosses and the generation of resistant and tolerant hybrids. A manual and papers on best practices and on controlling diseases and environmental stresses on basil are planned.
Impacts
What was accomplished under these goals?
Isolation of DNA from susceptible and resistant plants: Genomic DNA has been isolated from all genotypes, parents and generations demonstrating basil downy mildew (BDM) tolerance or resistance, as well as the susceptible sweet basil parent to which they have been hybridized. We are extracting DNA from approximately 120 genotypes from O. basilicum, O. x citriodorum, O. africanum, O. gratissimum, O. kilimandscharicum, O. tenuiflorum, O. campechianum and O. selloi. Scoring field plants for phenotypic traits and genetic resistance. Three field experiments across four locations. Inheritance of resistance to basil downy mildew (Pittstown, NJ & Bridgeton, NJ): The objective of this experiment was to determine the genetic basis for inheritance of downy mildew within our segregating BDMR (resistant) x BDMS (susceptible) full sib family. We evaluated parental, F1, F2, BC1P1 (backcross to susceptible parent) and BC1P2 (backcross to resistant parent) generations BDM response. Field response to BDM was measured using a rating system developed in 2013 for single plant evaluation. Diallel cross study of downy mildew tolerant and resistant genotypes (Riverhead, NY): The objective of this experiment was to measure field response to BDM among accessions demonstrating varying degrees of resistance (parents) as well as their F1 progeny. This experiment was performed at the Cornell Long Island Horticultural Research and Extension Center, Riverhead, NY (McGrath). Evaluation of F3 and BC1P1:F1 progeny (Belle Glade, Florida): The objective of this study was to evaluate progeny rows from downy mildew resistant selections advanced from the F2 and BC1P1 generations of the BDM resistant x susceptible family evaluated in 2013. Twenty progeny rows representing a ~4% of the most resistant/promising line from our 2013 base population were evaluated. Results confirmed that downy mildew resistance conferred by the resistant parent is effective across different environments. Our pedigree breeding strategy appears to be successful in generating stable resistance (homozygous resistance locus) as demonstrated by a consistent resistance response among individuals within some of our F3 progeny rows. Analysis of aromatic compounds: To assess gene action dictating inheritance of various essential oil components we analyzed segregation of major volatiles from the RU329 x SB22 mapping populations. The primary volatile constituent of BDM resistant parent RU329 is methyl chavicol (~70%), while the BDM susceptible sweet basil type was predominantly linalool (~60%). F2 BDM resistant plants were composed primarily of phenylpropanoids. Screen chilling tolerant OP and hybrids for chilling and Fusarium and cross chilling tolerant basils with Fusarium resistant basils, screen progeny: Nine Fusarium oxysporum isolates have been collected from Massachusetts, New Jersey Illinois, Connecticut and Italy. These isolates have now been used to infect susceptible basil cultivars to confirm virulence. Five have been confirmed to be virulent. Multiple cold screens at 4?C for 72 and 96-hr periods yielded four Rutgers breeding line demonstrating high tolerance (little or no visible injury). Screening commercially important basil varieties and other Ocimum spp. for BDM resistance: Development of a repeatable and accurate screening process (Pyne et al., 2014) has facilitated the identification of new genotypes resistant to downy mildew as well as O. gratissimum and O. kilimandscharicum. Conduct fungicide evaluations with products for conventional and organic production: In southern NJ at the RAREC station, conventional and experimental fungicides as well as different fungicide programs were examined for their efficacy against BDM. Results suggest significant differences in control based on fungicide, fungicide program, and application method. Fungicide evaluation. In NY, a replicated experiment was also conducted to evaluate new and currently registered fungicides for managing basil downy mildew conventionally or organically under field conditions. It was difficult to manage DM with an organic fungicide program, even when applications are started substantially before symptoms are found and applications are made 2x/week. In contrast, a high level of control (90-98%) was obtained with conventional fungicides applied on a preventive, weekly schedule. Eleonora did not exhibit any resistance to downy mildew when compared to Italian Large Leaf, in contrast with results obtained in 2013. Susceptibility of basil types and lines. Two replicated experiments were conducted in NY also to examine susceptibility to downy mildew of different basil types, breeding lines, and experimental resistant lines and results documented that highly effective resistance has been identified at Rutgers. The second experiment evaluated eight sweet basil experimental varieties developed by Enza Zaden Seed Company and two varieties from Johnny’s Selected Seeds. They were compared to DiGenova, a susceptible variety. None of the ten varieties evaluated were significantly less severely affected by downy mildew than DiGenova based on assessments of incidence of affected plants, incidence of leaves with symptoms, or severity at the final assessment. In Florida, concentrated on the early protection of sweet basil varieties grown under field conditions, principally beginning at emergence. Early trials looking at potential candidate fungicides for use as a seedling drench demonstrated two fungicides as being most efficacious, mefenoxam (Ridomyl Gold) and oxathiapiprolin (Experimental). Of the two candidates, Mefenoxam showed the best efficacy, exhibiting 100% residual control at the two higher rates for up to 3 weeks. Several other trials investigating the influence of Systemic Acquired Resistance Inducers (SARs) on basil downy mildew were also conducted. No combination of biopesticides and/or resistance provided economic control. Seed Quality and the Disease Pathogens BDM: At UMass, research focused on the genetics of the pathogen, and 32 basil seed samples were received in 2014 and tested for P. belbahrii by qPCR. Twelve samples (37.5%) tested positive. Three of the positive samples were from seed lots that had previously tested positive and were re-sampled after steam treatment. qPCR will detect pathogen DNA regardless of whether or not the pathogen is alive. P. belbahrii can be unevenly distributed in a seed lot and very few sporangia may be present. Screen basil seed for Fusarium oxysporum f. sp. basilici: At UMass the Ma’s lab is currently engaged in sequencing the genome of an isolate of F. oxysporum f. sp. basilici. Isolates previously collected from basil seed have been stored as conidia in silica crystals. Investigate genetic diversity of P. belbahrii: 78 samples of P. belbahrii on basil leaves were submitted to the lab in 2014 (1 from Mexico and 77 from USA). DNA was extracted and PCR was performed with four different primer sets; amplification frequently did not produce useful sequences, possibly because of sample contamination with DNA from other organisms and the non-specific nature of the primers used. We are currently repeating PCR with two new primer sets (Belbahrii et al., 2005). Pseudozyma, potential innovative control agent: A species of Pseudozyma has been observed colonizing sporangiophores of P. belbahrii on infected basil leaves. Scanning electromicrographs of basil leaves colonized by both organisms show that the hyphae of Pseudozyma wrap around sporangiophores and appear to penetrate plant tissue through the stomata. Transformation of the yeast with green fluorescent protein (GFP) was successful.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Homa, K., Wyenandt, C. A., Barney, W. P., Ward, D. L., and Simon, J. E. 2014. Evaluation of fungicides for the control of Peronospora belbahrii on sweet basil in New Jersey. Plant Disease, 98(11):1561-1566.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Pyne, R.M., A. Koroch, A. Wyenandt and J.E. Simon. 2014. A rapid screening approach to identify resistance to basil downy mildew (Peronospora belbahrii). HortScience 49:1041-1045.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Novaes, M. I. C., J. S. Patel, and S. Zhang. 2014. Evaluation of oxathiapiprolin (QGU42) at different rates for management of downy mildew of basil under greenhouse conditions. Plant Disease Management Reports 8: V208. doi:10.1094/ PDMR08
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Patel, J. S., S. Zhang, M. Barbier, and M. Paret. 2014. Efficacy of biopesticides and difenconazole for managing downy mildew of basil, 2013. Plant Disease Management Reports 8: V207. doi:10.1094/ PDMR08
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
McGrath, M. T. and LaMarsh, K. A. 2014. Evaluation of downy mildew-resistant basil cultivars, 2013. Plant Disease Management Reports 8:V270.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
McGrath, M. T. and LaMarsh, K. A. 2014. Evaluation of organic and conventional fungicides for downy mildew in basil, 2013. Plant Disease Management Reports 8:V191.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
McGrath, M. T., LaMarsh, K. A., Simon, J., Pyne, R. M., and Wyenandt, C. A. 2014. Assessment of downy mildew susceptibility in basil cultivars, breeding lines, and crosses in New York, 2013. Plant Disease Management Reports 8:V269.
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Progress 09/01/12 to 08/31/13
Outputs
Target Audience: We had four targeted audiences to whom our work is being addressed and whom are receiving information from the researchers involved in this program. The first are the commercial growers; the second are the home gardeners, the third are those from the commercial private sector serving to support the commercial growers (e.g. seed companies, those involved in developing chemical and organic controls for basil downy midlews, and buyers for fresh sweet basil); the fourth are other researchers and scientists including plant breeders and those plant pathologists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Monitoring program. In 2009 a program was started to obtain information on where basil downy mildew occurs and to try to determine whether the pathogen could move northward through the eastern USA, now that it is considered established in FL, as occurs with the cucurbit downy mildew pathogen, and whether a monitoring program can assist growers to be prepared for downy mildew occurrence in their basil crop. Monitoring also will assist with determining whether seed is becoming a less important source, as expected. Each year a spreadsheet accessible by anyone has been set-up in Google Docs. The link is posted in an article about the disease, which is also up-dated annually. It is at http://vegetablemdonline.ppath.cornell.edu/NewsArticles/BasilDowny.html. In addition to date and location of the occurrence, growers and gardeners making reports have often included information about the occurrence and management experience, all adding to knowledge about this new disease. Those reporting are asked to include their e-mail address. As part of the SCRI project, everyone reporting has been contacted to obtain more information and provide assistance with diagnosis to confirm the report. The monitoring program has resulted in samples being obtained for project PI R. L. Wick for his investigation of biodiversity in the pathogen. There were 64 reports posted in 2013. These documented occurrence of basil downy mildew in the USA in CA, CT, DC, FL, IL, LA, MA, MD, ME, NH, NJ, NY, OH, RI, SC, TN, VA, VT, WI, and WV. A report was also made from Australia. In each state (Florida, Massachusetts, New Jersey), field trials were conducted as training and demonstrations for commercial growers, seed companies and the public. Trainings in basil downy mildew identification and control were provided also in winter grower schools and summer field days, twilight meetings. How have the results been disseminated to communities of interest? In each state (Florida, Massachusetts, New Jersey), field trials were conducted as training and demonstrations for commercial growers, seed companies and the public. Trainings in basil downy mildew identification and control were provided also in winter grower schools and summer field days, twilight meetings. Some examples follo Presentations at scientific meetings · ACMAP (American Council for Medicianlly Active Plants). 2013, Variation of essential oil constituents and antioxidant capacity in a segregating basil (Ocimum spp.) population. (Robert Pyne, H. Rodolfo Juliani, Adolfina R. Koroch, and James E. Simon, poster presentation). 4th nnual Conference. June 2-5, 2013. University of Massachusetts, Amherst, MA. · ASHS (American Society for Horticultural Science). 2013. Identification of Host Resistance to Basil Downy Mildew (Peronosporabelbahrii) Robert Pyne, Adolfina Koroch, James E. Simon and Andrew Wyenandt. Annual Conference . July 22-25, 2013 Palm Desert, California · Flavor, Fragrance & Fragrance Conference. Breeding as a tool for generation of novel aromas in basil (Ocimum spp.) (Robert Pyne, H. Rodolfo Juliani, Adolfina Koroch, Thomas Villani and James Simon) 2nd Annual conference: September 12, 2013. · Zhang, S., Z. Mersha, R. N. Raid, Y. Fu, X. Liao, and J. S. Patel. 2013. Downy mildew of basil in US: What have we learned so far? The 10th International Congress of Plant Pathology, Beijing, China. August 29. · Zhang, S., Z. Mersha, R. N. Raid, Y. Fu, X. Liao, and J. S. Patel. 2013. An overview of basil downy mildew research in US. International Downy Mildew Group meeting, Beijing, China. August 27. · Zhang, S. 2013. Research on downy mildew of basil in US. Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China. September 6. · Zhang, S. 2013. An overview of research on downy mildew of basil at TREC. The 13th Biennial Meeting of the Florida Phytopathological Society, Davie, FL. May 8. · Mersha, Z., and S. Zhang. 2013. Tank mix and alternation of acibenzolar-S-methyl with reduced rates of mandipropamid for control of downy mildew on basil in the greenhouse. The Annual Meeting of APS, Austin, TX. August 10-14. (Poster) · Patel, J. S., S. Zhang, and Z. Mersha. 2013. Effect of plant age on downy mildew of basil. The Annual Meeting of APS, Austin, TX. August 10-14. (Poster) · Patel, J. S., M. I. Costa de Novaes, and S. Zhang. 2013. Management of downy mildew of basil by seed treatment with oxathiapiprolin. The Annual Meeting of APS, Austin, TX. August 10-14. (Poster) · Mersha, Z. and S. Zhang. 2013. Incubation and latent periods of basil downy mildew (Peronospora belbahrii) as affected by temperature and wetness duration. The 2013 APS North Central Division Meeting, Manhattan, KS. June 12-14. (Poster) · Zhang, S. and J. S. Patel. 2013. Sustainable disease management of basil downy mildew by using biological and chemicals including a new chemistry. Basil Workshop, Homestead, FL. December 19, 2013. · Mersha, Z. and S. Zhang. 2013. Alternation and tank mix of acibenzolar-s-methyl with azoxystrobin or mandipropamid to control basil downy mildew. Basil Workshop, Homestead, FL. December 19, 2013. · Raid, R. N. and S. Zhang. 2013. Effectiveness of fungicide soil drenches for management of basil downy mildew. Basil Workshop, Homestead, FL. December 19, 2013. · Results from National Basil Downy Mildew Monitoring Program and Evaluating Fungicides and Resistant Varieties in New York. Basil Workshop, Homestead, FL. 12/20/13. · Phosphorous Acid Fungicides: What Are The Best Uses? In the Vegetable Track Session on “Insect, Weed, and Disease Management Updates”. CCE Agriculture and Food Systems In-Service. Ithaca, NY. 11/21/13. · Organic Disease Management: Concepts & Facts Beginning Farmers Need to Know. Advanced Organic Vegetable Production Session for Beginning Farmer Service Organization Professional Development Training. Latham, NY. 10/30/13. Webinar Seminars, Teaching Practicums and Live Workshops · Homa, K., Simon, J.E., Wyenandt, A., Barney, W.P. (2014). Evaluating fungicides for the control of basil downy mildew; breeding for resistance to basil downy mildew.In: NJ Vegetable Growers Meeting,Atlantic City, NJ. · Homa, K., Pyne, R., Wyenandt, A., Simon, J.E., Koroch, A.R. (2013). Evaluation for fungicides for the control of basil downy mildew; Genetics of basil breeding for resistance and tolerance to downy mildew, chilling injury and fusarium wilt. In: Basil Downy Mildew Workshop hosted by UFL. Homestead, FL. · Pyne, R. and Simon, J.E.. (2012). (2012) Breeding for resistance to basil downy mildew.In: NJTwilight Meeting. Rutgers Agricultural Research and Education Center,Bridgeton, NJ & The Snyder Research and Extension Farm , Pittstown, NJ. · Homa, K., Pyne, R., Wyenandt, A., Simon, J. (2013). Controlling Downy Mildew.13 May2013.Plant & Pest Advisory, Rutgers Cooperative Extension[online]. Available from: · Homa, K., Simon, J.E., Wyenandt, A., Barney, W.P. (2013). Evaluating fungicides in 2012 for the control of basil downy mildew.In: NJ Vegetable Growers Meeting, Atlantic City, NJ. · Homa, K., Barney, W.P., Wyenandt, C.A. (2012). Evaluating fungicides for the control of basil downy mildew and evaluatingOcimumspecies, cultivars and breeding lines forsusceptibility to basil downy mildew.In: NJ Vegetable Growers Meeting,February 2012,Atlantic City, NJ. · Homa, K. (2012). 2012 Fungicide efficacy trials for control of basil downy mildew.In: NJTwilight Meeting. 2012. Rutgers Agricultural Research and Education Center,Bridgeton, NJ Disease Diagnosis and Management in the Home Vegetable Garden. Master Gardener Training Program, Great River, NY. 3/27/13 What do you plan to do during the next reporting period to accomplish the goals? Continued focus on plant genetics and breeding. Isolate and identify the genetic markers associated with resistance and susceptibiity of basil downy mildew in basils. Contined focus on developing new and more sweet basils resistant to basil downy mildew that also have excellent aroma, flavor and taste (aromatic volatiles and more) and market characteristics (leaft shape, curvature, and texture). Examine whether the chilling tolerance and the fusarium resistance was inherited along with or retained in the new basil downy mildew resistant plants. From a pathological perspective, examine whether there is one or multiple races of the basil downy mildew pathogen. Continue to examine management techniques to mitigate or eliminate basil downy mildew with chemical control agents and other approaches. Survey the commercial growers for economic base-line losses of this and other diseases. Develop practical food safety guidelines around the use of chemicals associated with the control of basil downy mildew.
Impacts
What was accomplished under these goals?
Isolating DNA from susceptible and resistant plants: A standardized protocol was first developed for DNA extraction based upon a CTAB method modified from Murray and Thompson, 1980 to yield an average of approximately 30 micrograms of DNA/100 mg fresh weight sample. DNA from young leaves from resistant and susceptible plants were extracted using a modified CTAB protocol (Viera et al., 2003). Absorbance was measured for all samples using the ThermoScientificNanodrop spectrophotometer to measure DNA quality and quantity. This protocol was used to extract DNA from parents, F1, F2, and backcross populations (over 30 lines), as well as other accessions from the USDA and Rutgers basil germplasm. Screening for polymorphic EST and scoring progeny for mapping: We extracted DNA from bulked leaf tissue of four resistant and susceptible parents, as well as their F2 and backcross populations segregating for resistance to downy mildew. For the bulked segregant analysis, plants with 0.08 S DSI or less were considered resistant, while plants with an S DSI of 0.96 or greater were considered susceptible. While screening for polymorphism in the parents, we are simultaneously screening the DNA bulks with the goal of finding a marker monomorphic for among downy mildew resistant plants. Score field plants for phenotypic traits: Cornell University conducted replicated experiments under field conditions to evaluate organic and conventional fungicides and to examine susceptibility of different basil types, breeding lines, and experimental resistant lines.The objective of one experiment was to compare susceptibility of several spice types of basil, Rutgers breeding lines, and crosses made by the project scientists working on developing resistant varieties at Rutgers Downy mildew became severe on DiGenova. Some lines being used to breed downy mildew resistant sweet basil exhibit a very high level of resistance under environmental conditions on Long Island, and a good to excellent level of resistance is being obtained in crosses produced at Rutgers. Experiment 2 evaluated six sweet basil experimental lines of Enza Zaden seed company. All lines showed BDM symptoms. A field trial was also conducted at Rutgers to determine the heritability and mechanism of genetic resistance to basil downy mildew. The trial included two families, each with F2 and backcross populations, generated from crossing resistant (selected Rutgers lines) and susceptible (selected RU lines SB22 and CB10) parents. Plus, five additional inter- and intraspecific hybrids were evaluated for response to downy mildew. Crosses were made in reciprocal to evaluate potential maternal effects. The treatment structure was an augmented factorial array with three treatment classes: family, generation and resistant/susceptible mother. The experiment was structured in a completely randomized design in which parental generations, F1 generations and highly susceptible control plants (O. basilicum ‘DiGenova’) were in triplicate, backcross and F2 populations. Results show a high proportion of individuals in the F2 and BC1F1 populations generated from one cross demonstrating low disease severity. This suggests that some level of dominance is involved in the inheritance of downy mildew resistance. In contrast, populations from another cross show a greater proportion of plants with high disease severity. Analysis of aromatic volatiles from the basil plants: Essential oils of commercial varieties, Rutgers breeding lines and other collected accessions have been analyzed using Gc/MS analysis (Juliani et al, 2008). This catalogue of volatile profiles has been particularly useful to our breeding efforts by allowing for the quantification of terpene and phenylpropene constituents required for an acceptable sweet basil. Downy mildew resistant lines identified to date group with non-traditional essential oil profiles, which presents a challenge when incorporating such lines into a breeding strategy. We began to analyze profiles of our downy mildew breeding populations. As expected, results suggested that phenylpropene dominance over terpenoids will continue to the F2 generation. Screen chilling tolerant OP and hybrids for chilling and Fusarium and cross chilling tolerant basils with Fusarium resistant basils, screen progeny: Selection of parents for breeding populations was chosen such that parents were polymorphic for as many traits as possible. Although response to downy mildew was given the greatest priority when making parental selections, Rutgers fusarium wilt resistant and chilling tolerant lines were incorporated into crosses of all major breeding populations. Conduct fungicide evaluations with products for conventional and organic production: Replicated experiments were conducted to evaluate new and currently registered fungicides for managing basil downy mildew conventionally or organically under field conditions. At Corenll, downy mildew was not suppressed by products suitable for organic production: a program with currently registered fungicides (Regalia soil drench followed by foliar applications of Actinovate alternated with Trilogy) and a fungicide in development (Bioguard applied to soil and foliage). The other biopesticide tested, ProPhyt, a phosphorous acid fungicide, was effective based on the last assessments. The most effective conventional fungicide treatments consisted of a soil drench of ProPhyt or Regalia followed by foliar applications of Zorvec. These treatments were not significantly better than Zorvec used alone or than foliar treatments with Zampro, Revus, or Ranman. Ranman applied in alternation with Fracture was not as effective as the best treatments. Presidio was ineffective. These five fungicides are registered in the USA; only Ranman is labeled for use for basil downy mildew at this time. At Rutgers fungicides were evaluated as foliar treatments applied on a weekly basis. A few of these fungicides were additionally evaluated for their efficacy against basil downy mildew when applied as weekly drip applications. Phosphite fungicides (K-Phite, Rampart, Prophyt) and Ridomil Gold (mefenoxam, 4) were evaluated as weekly foliar or weekly drip applications in separate trials. The foliar-applied phosphite fungicides provided a comparable level of control to foliar-applied Ridomil Gold. Phosphite fungicides (K-Phite, Rampart, Prophyt) applied weekly via drip provided variable levels of downy mildew control compared to each other and were less effective compared to Ridomil Gold. Screen basil seed for P. belbahrii and investigate genetic diversity: From UMass: About 200 basil seed samples have been collected to date. Of 140 seed samples tested 11.4% were positive for Peronospora belbahrii. Samples received from seed companies had a much higher incidence of contamination; of 52 samples, 46% were tested positive for the downy mildew pathogen. We have found that the PCR assay and the qPCR assay has been inconsistent and thus many of the tests were run multiple time. We are currently running head to head comparisons with qPCR, nested conventional PCR and a combination of both assays. Currently we are using a Fusarium-selective medium (Komada) for the detection of Fusarium in basil seed. All fusaria cultured are then tested on basil plants to determine if they are pathogenic. In previous work we developed probes and primers for the detection of Fusarium and we will be carrying out quality control tests to incorporate this assay into our program. To date only one basil seed sample has tested positive (Koch’s postulates) for Fusarium.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Adolfina R. Koroch, Thomas S. Villani, Robert M. Pyne, and James E. Simon. 2013. Rapid Staining Method to Detect and Identify Downy Mildew (Peronosporabelbahrii) in Basil. Applications in Plant Sciences 1(7): 1300032. http://dx.doi.org/10.3732/apps.1300032
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Mersha, Z., S. Zhang, Y. Fu, X. Mo, R. N. Raid, and B. Hau. 2013. Efficacy of acibenzolar-S-methyl and ?-amino-butyric acid for control of downy mildew in greenhouse grown basil and peroxidase activity in response to treatment with these compounds. Journal of Phytopathology 161: 154-164.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Patel, J. S., M. I. Costa de Novaes, Y. Fu and S. Zhang. 2013. Evaluation of chemicals and biologicals for control of bacterial spot of tomato under greenhouse conditions. 2013. Plant Disease Management Reports 7: V148. doi: 10.1094/PDMR07.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Patel, J. S., M. I. Costa de Novaes, M. Barbier and S. Zhang. 2013. Evaluation of biopesticides for managing downy mildew of basil. Plant Disease Management Reports 7: V147. doi: 10.1094/ PDMR07.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
McGrath, M. T. and LaMarsh, K. A. 2013. Evaluation of fungicides for managing downy mildew in basil, 2012. Plant Disease Management Reports 7:V015.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2014
Citation:
McGrath, M. T. and LaMarsh, K. A. 2014. Evaluation of fungicides for managing downy mildew in basil, 2013. Plant Disease Management Reports 8:(accepted).
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: This project seeks to develop a public and private sector consortium with University of Florida, University of Massachusetts with Rutgers to improve the sweet basil industry in the USA which has been seriously impacted by a new devastating disease, basil downy mildew and continues to be constrained by fusarium disease and chilling sensitivity. In this first year of this USDA SCRI funded project, activities included establishing field and greenhouse studies in three states, building a specialized screening facility at Rutgers to culture BDM, screen plants to controlled concentrations of BDM and retrofit new facilities for screening chilling tolerance. Parallel field and greenhouse studies were conducted to identify fungicides that could mitigate or control BDM. Staff and students were brought into the program and we mentored graduate students; and gave extension presentations in all the partner states. Field trials established at the Rutgers Agricultural Research and Extension Center (RAREC) in Bridgeton, New Jersey looked at a wide range of chemical control agents while separately 42 basils, including 4 Rutgers breeding lines, 10 USDA accessions and 30 commercial cultivars, were made so as to exploit the diversity within the genus (Ocimum spp.). The field was inoculated by natural infection and symptoms later scored. Nine O. americanum accessions USDA accessions plus three USDA O. gratissimum) were resistant, showing no chlorosis or sporulation at any time. All O. citriodorum accessions and two USDA accessions, PI 253157 and PI 173746, experienced chlorosis and black necrotic spots, but limited sporulation. As all lines screened of O. basilicum show susceptibility, we used the most tolerant lemon basil, cv. Sweet Dani, and crossed it with O. basilicum and generated F1 progeny. A mapping population is being developed through purposeful inter- and intraspecific crosses. An emphasis in our breeding program has been placed on hybridization of basil downy mildew tolerant (very low incidence of chlorosis and sporulation) species, Ocimum americanum cv. Spice and Ocimum citriodorum cv Sweet Dani, to the susceptible O. basilicum cv DiGenova (very low incidence of chlorosis and sporulation), and advanced Rutgers breeding lines (chilling tolerant and fusarium resistant). interspecific O. basilicum crosses have been made between Rutgers chilling tolerant and Fusarium resistant breeding lines and cv DiGenova. This may allow for a more stable genetic system in which to work within the genus as compared to interspecific populations. Currently, there are 14 F1 populations from 12 different parents. Parents were cloned and are being maintained in the Rutgers research greenhouse. F2 and backcross pollinations have been made and populations will be generated in the first quarter of the second year. DNA is being isolated from parents and progeny (F1) of the potential mapping populations. Research continued to focus on developing chilling tolerant sweet basil. New selections and hybrids of chilling tolerant basils (4C for 72 hrs) were made. Sister lines of our Poppy Joes Sweet Basil, an OP tolerant to fusarium were evaluated and found to remain chilling tolerant. PARTICIPANTS: In this project, Drs. Simon and Wyenandt from Rutgers serve as the Project PIs. Simon leads the genetic and varietal work and Wynandt the pest control work. Genetics of the basil downy mildew (BDM) pathogen are led by Drs. Wick and Ma (UMass). Field and greenhouse studies are lead by Drs. Raid and Zhang (UF), McGrath (Cornell) and Simon/Wyenandt (Rutgers). Economic analyses and crop budgets and associated costs of using pesticides is led by Dr. Govindasamy (Rutgers). Extension and outreach is lead by Drs. Bill Sciarappa, Wes Kline and Rick VanVranken for New Jersey growers; Mangan (UMass) for Massachusetts growers; McGrath (Cornell) for New York Growers, and Raid and Zhang for Florida growers. Dr. Koroch, BMCC, CUNY, and graduate student Robert Pyne are involved extensively in the genetic studies and breeding. Others are involved in nutrition and supportive work (Drs Juliani and Wu, Rutgers) and others in field work (Dr. Park and R. Pyne, Rutgers). This project is done with cooperation with seed companies (e.g. Johnny's; Stokes, Enza, others), produce buyers and others involved in the culinary herb industry. TARGET AUDIENCES: Target audiences include commercial growers and seed companies(in USA), growers, processors and buyers and traders involved in the basil, fresh herb and processed herb industries. Relevance of this work also is aimed at home gardeners and horticulturalists given the diseases impact everyone growing and interested in basil. For our supportive service and collaborative role, our stakeholders also include other scientists, county, regional and state extension specialists. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our mission is to provide tools and strategies to commercial basil growers and toward that end we have identified several chemical control agents that can reduce and mitigate against BDM as all sweet basils are highly susceptible. We also made progress on developing genetic resistance to BDM in sweet basil (O. basilicum). Confirmation of chilling tolerant lines and hybrids allow us to do further selection and breeding.
Publications
- No publications reported this period
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