Source: NORTH CAROLINA STATE UNIV submitted to NRP
ADVANCED SYSTEMS FOR INTEGRATED MANAGEMENT OF STRAWBERRY SOILBORNE PESTS IN THE SOUTHEAST USA
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
0227112
Grant No.
2011-51102-31142
Cumulative Award Amt.
$496,962.00
Proposal No.
2011-04737
Multistate No.
(N/A)
Project Start Date
Sep 1, 2011
Project End Date
Aug 31, 2015
Grant Year
2011
Program Code
[112.C]- Methyl Bromide Transitions Program
Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695
Performing Department
Plant Pathology
Non Technical Summary
Over the years we have assembled an inter-disciplinary and inter-state response and vision team of key private and public sector stakeholders that seeks to implement chemical and biological-based alternatives to methyl bromide. Significant progress has been achieved in vegetable and strawberry production issues. This proposal focuses on advancing strawberry production systems by developing and extending readily adaptable fumigant and biologically-based approaches. Three strategic levels of research and extension are identified to address critical use nominations for the strawberry fruit industry in the Southeast USA: 1) Tactic substitution - addressing short term needs of growers who seek non-ozone depleting fumigant alternatives. The primary component includes fine-tuning the use of novel mulches and technologies to enhance efficacy and/or mitigate emerging regulatory issues; 2) Tactic Diversification - focuses on advancing current research efforts to incorporate novel and registered fungicides, nematicides and herbicides using pest-driven combinations for targeted and efficacious management of these soilborne pests; 3) Tactic Development - focuses on readily adaptable and biologically-based systems including use of best management systems with cover crops and compost, anaerobic soil disinfestation, mustard seed meal applications and biased soil profiles that favor beneficial microbial communities. Finally, we will focus on extending outcomes through multi-tactic mechanisms including participatory on-farm-research, web-based information, extension agent training, field days, presentations at most fruit and vegetable meetings in the SE and along the eastern seaboard, scientific presentations at professional meetings, peer reviewed publications, and writings in extension articles and industry driven newsletters. Combined efforts are expected to result in technically and economical feasible assessments and implementation of alternatives, exploration of viable diversification and development of integrated pest management tactics, and a region-wide advanced understanding of the biology, ecology and management of key soilborne pests.
Animal Health Component
60%
Research Effort Categories
Basic
20%
Applied
60%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2051122116060%
2051122107020%
6011122301020%
Knowledge Area
601 - Economics of Agricultural Production and Farm Management; 205 - Plant Management Systems;

Subject Of Investigation
1122 - Strawberry;

Field Of Science
1070 - Ecology; 1160 - Pathology; 3010 - Economics;
Goals / Objectives
The strawberry industry in the Southeast region (SEUS; north of Florida) tends to consist of many limited acreage (5 acres average) growers who depend on this spring crop as a major source of their farm gate income (Safley et al. 2004). Costs of production can reach $13,000 or more per acre with gross returns of $15,000 to over $17,000 per acre if pests, particularly soilborne pathogens and weeds, are managed well (Sydorovych et al. 2006). In the absence of effective management net returns are reduced by over $8000 per acre (Sydorovych et al. 2006). Critical use nominations (CUN) to extend the use of methyl bromide as a soil fumigant were developed for the SEUS (AL, AK, GA, KY, LA, MS, NC, OH, SC, TN) through a participatory and industry-wide stakeholder process and the lack of adoption of alternatives was due to: 1) lack of confidence or data in about the alternatives, 2) costs of alternatives, 3) application difficulties due to such factors as hilly terrain, equipment requirements or weather patterns, 4) certain alternative fumigants cannot be used in environmentally sensitive areas, 5)current or emerging regulatory restrictions and 6) extensive pest pressure not sufficiently managed by alternatives. In addition, we are encountering many growers who are actively seeking non-fumigant based approaches to manage their crops and circumvent these (perceived or real) issues. Thus, it is critical that we continue to expand our research and extension efforts in fumigant and non-fumigant based systems. Our long-term goal is to foster a strawberry industry that is competitive, sustainable, and conducive to SEUS farm viability. Such a vision encompasses short, mid- and long-term outcomes and is dependent on the diverse stakeholder objectives identified. Our objectives are i) to enable growers to transition to economically and technically viable non-ozone depleting fumigants; ii) to develop and/or implement other chemical-based tactics or non-chemical-based tactics extendable in the near term to effectively manage economically constraining soilborne pests and improve crop performance; iii) to enable growers to adapt to economically and technically viable biologically-based systems to complement fumigant and chemical inputs or to supplant them and iv) to effectively extend research-based information to stakeholders. Outputs will include training of field faculty, extension agents and other key consultants, frequent symposium and grower meeting presentations, extension publications and products, and scientific peer review publications that advance the science of strawberry production and soilborne pest management. Safley, C.D, E. B. Poling, O. Sydorovych, F.J. Louws, G.E. Fernandez, and L.M. Ferguson. 2004. Estimated costs of producing, harvesting, and marketing strawberries in North Carolina. Agricultural and Resource Economics Report Number 28, North Carolina State University, Raleigh, NC p 26. Sydorovych,O., C.D. Safley, L.M. Ferguson, E. B. Poling, G.E. Fernandez, P.M. Brannen, D.M. Monks and F.J. Louws. 2006. Economic evaluation of the methyl bromide alternatives for the production of strawberries in the Southeastern US. HortTechnology 16:118-128.
Project Methods
Objective 1: We will continue to explore the use of existing or novel fumigants for efficacy against the major soilborne diseases and weeds of strawberries in combination with existing and emerging technologies such as types of mulch and application methods. We propose to incorporate reduced rate treatments in our field scale work through on farm research (OFR). Objective 2: We seek to determine the viability of using "smart" timing and judicial use of products to manage soilborne pests in strawberry production systems optimally applied to manage site-specific strawberry pests. We have been evaluating novel chemistry and technologies that we believe can play a major role in future non-fumigant dependent strawberry production systems. Likewise, we have documented strawberry crop phenology and know when strawberry plants have root growth spurts - providing an informed criteria of when optimal fungicide/pesticide timings can be applied. Therefore, we propose to design programs that combine our knowledge and experience about the biology of the pests, pesticide efficacy and use patterns, crop growth cycles and critical pathogen-free periods to develop non-fumigant approaches to manage targeted soil pests. Objective 3: There is a need to expand research and extension on the potential of anaerobic soil disinfestation as a tool to manage soilborne pests in SEUS strawberry production systems. There is also a need to further explore the efficacy of using mustard seed meal (MM) as a component of biologically-based systems to manage soilborne pests in strawberry production systems. We will use land with a long-term history of strawberry production in TN and NC on growers' fields and on research station land and implement various farming system practices that rely on cover crops, organic amendments and best management practices to enhance strawberry production. This work will be complemented with detailed soil and microbial community analysis. For the field work, we will collect weed and disease incidence data, whole plant samples, and our team or growers will collect yields, typically collected twice weekly. Treatments will be replicated in a RCDB and in some cases for OFR, growers will allow non-fumigate treatments. Local agents will be engaged to help collect data. Objective 4: Growers prefer production systems that offer improved economic performance (lower costs, higher yields, reduced inputs, and improved quality), as well as reduced risk. Therefore, we will evaluate economic performance of the proposed biological-based and chemical alternatives to MeBr by using partial budget and net economic value methods. The proposed analysis methods would allow our team to isolate, identify and value all economic gains and losses associated with each system and to assess system profitability. We will also adopt multiple methods to communicate research-based outcomes consistent with the history of our programs including agent training, symposiums, grower meetings/expos, extension publications and products and peer reviewed scientific publications.

Progress 09/01/11 to 08/31/15

Outputs
Target Audience:Multiple target audiences were reached as an impact of this project. First and foremost the target audience was strawberry growers and their supporting industries in the Southeastern USA (SEUS) and surrounding regions, especially these impacted by the loss of methyl bromide as a soil fumigant. These states included AL, AK, GA, KY, LS, MS, NC, SC, TN and OH but outputs and impacts were also provided for stakeholders in CA and Ontario, Canada and multiple other international growers and stakeholders. The efforts that engaged stakeholders included multiple on-farm-research projects primarily in TN and NC. In these projects growers helped to define treatments, helped manage the project and enabled collection of scientifically valid data based on the statistically valid design of experiments and shared collection of data. Growers also participated in local and regional strawberry meetings to translate experiences and observations to a wider audience. Second, project outcomes were packaged into project outputs that included extension articles in industry newsletters and publications (3), extension articles that detailed major soilborne diseases and management recommendations (15) and presentations at multiple local, regional and national grower meetings (13). These products typically emphasized an IPM and sustainable agriculture context to advance strawberry production systems and management of soilborne problems. A second major audience that detailed projects outcomes and impacts includes other scientists and international stakeholders. This audience was reached through peer-reviewed articles, 5 scientific abstracts or proceedings at national or international meetings and 7 invited talks including 4 presentations in international settings (Netherlands, South Africa, 2 in China). The project also emphasized train-the-trainer activities through a cooperative Extension Training program held in AR (May 2014) and NC (Feb 2013) with agents from a SE regional area. Finally, the program targeted and provided training for graduate students, undergraduate students, postdoctoral scientists, senior scientists and staff. These personnel benefitted through enhanced educational and career opportunities. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Multiple levels of training and professional development were achieved. First, strawberry growers and associated industry were engaged and trained about the biology, ecology and management of strawberry root and crown rot pathogens and were trained concerning the most up-to-date management recommendations. Over 13 talks were provided related to management of soilborne pests in a wide range of grower and professional meetings in AR, NC, SC, OH, OK, VA and Ontario. In many cases these were single talks but in 2012 Dr. Carl Sams and Frank Louws co-organized a fumigation alternatives and soil amendments workshop at the Southeastern Strawberry Growers Conference, typically attended by over 250 growers and industry personnel. We were also engaged in several agent training programs linked with other programs (GA) or as stand-alone training in AR and NC, in conjunction with the Walmart Strawberry Sustainability Projects or the Southeastern Small Fruit Consortium. The project also employed 5 or more undergraduate students; 1 achieved State ranking in an undergrad research symposium related to strawberry fumigant alternatives work and went on to the National Undergraduate research Symposium, then secured a job with Bayer; another went on for his Ph.D. in chemistry, another went to medical school and the Peace Corps and another became a clinical research coordinator. We also trained a postdoctoral employee who commenced her work on this project as an NSF self-funded employee and could be ranked as an outstanding scholar; also a senior research scientist who managed components of the project and secured a job with a private seed/breeding company. We also trained technicians: one secured enough expertise to commence his own business in product evaluation on horticulture/agronomic crops and a second became a lab manager in a large lab facility. One graduate student was trained (TN) and secured expertise in analytical chemistry techniques to develop, carry-out, and analyze her research; conducted field, greenhouse, and lab trials and operated and maintained high performance liquid chromatography instruments. She also assisted undergraduate research assistants with proper training of analytical procedures and managed upkeep and supply demand in our lab.? How have the results been disseminated to communities of interest?Dissemination of results was a critical component of this project. First, MeBr alternative recommendations were incorporated into our Southeastern Strawberry IPM Guide (smallfruits.org/smallfruitsregguide; see products). These details enable growers to make decisions regarding fumigant and IPM-based decisions to manage soilborne pests. Second, a series of factsheets were generated that highlight advanced knowledge about the diagnosis, biology and management of soilborne pathogens (strawberries.ces.ncsu.edu/strawberries-diseases); among other major disease challenges growers face. These factsheets are linked to a diagnostic tool growers can use to diagnose their strawberry problems (diagnosis.ces.ncsu.edu/strawberry). These products were complimented by industry newsletter articles (3), agent training programs, multiple grower presentations (13 +) and multiple invited and international presentations (7+) related to the challenge of managing soilborne diseases of strawberry. Strawberry growers across the eastern seaboard in particular, have recurrently featured our data and recommendations in their meetings and this program enabled dissemination of novel and emerging recommendations to serve growers well. Examples of grower presentations include: Vollmer, R., F. Miller and F.J. Louws. Benefits and challenges of growing certified organic strawberries. Southeast Strawberry Expo. 17 Nov, 2015. Louws, F.J. Strawberry diseases: Biology and Integrated management. Oklahoma - Mid-western Strawberry Conference. February 28, 2015. (webinar). Louws, F.J. Current recommendations for managing diseases of strawberries. Virginia Beach Strawberry School. February 24, 2015 (webinar). Louws, F.J. Strawberry diseases: Biology and Integrated management. 6thAnnual Mid-South Commercial Horticulture-- Fruit Producers Meeting. Conway AR. (webinar). January 29, 2015. Louws, F.J. Q&A Panel on Strawberry Diseases and Issues.6thAnnual Mid-South Commercial Horticulture-- Fruit Producers Meeting. Conway AR. (Webinar). January 29, 2015. Louws, F.J. Chair of Session: Managing soilborne diseases. Southeast Strawberry Expo. November 18, 2014. Louws, F.J., A. Torres-Barragan, T. Quintero. Biopesticides: What are they and how do they work? North American Strawberry Growers Annual Meeting; Southeast Strawberry Expo 2013. December 5, 2013. Durham, NC. Louws, F.J., A. Torres-Barragan, M.S. Schroeder-Moreno. Soil health management and IPM. North American Strawberry Growers Annual Meeting; Southeast Strawberry Expo 2013. December 6, 2013. Durham, NC. Louws, F.J. Strawberry fumigation and methyl bromide alternatives. Ohio Produce Growers and Marketers Association Congress. January 21, 2013. Louws, F.J. IPM for Organic Strawberry Productions: Managing Diseases. 32ndAnnual AR & OK Horticulture Industries Show. Fort Smith, AR. January 12, 2013. F.J. Louws and C. Sams. Options for Non-fumigation in strawberries. Southeast Strawberry Expo 2012. November 10, 2012. Charlotte, NC. F.J. Louws. Fumigation and non-fumigation alternatives. Southeast Strawberry Expo 2011. November 8, 2011. Durham, NC. F.J. Louws. New 2012 fumigation regulations. Southeast Strawberry Expo 2011. November 8, 2011. Durham, NC. (session organizer). Examples of Invited and International Talks include: Louws, F.J. 2015. (submitted talk). Integrated management of black root rot of strawberry: pathogen diversity and farming system solutions. 8thNorth American Strawberry Symposium and 39thNorth American Strawberry Growers Association. Ventura, CA. February 5, 2015. Louws, F.J. 2014. IPM of tomato and strawberry soilborne pathogens: The interplay between science and practice. Soilborne Plant Diseases Symposium: Integrated Management and Soilborne Plant Diseases. Stellenbosch, South Africa, Sept 10-11, 2014. Louws, F.J. 2014. Integrated management of soilborne pathogens: From practice to science and back again. Huazhong Agricultural University, Wuhan, China, March 19, 2014. Louws, F.J. 2014. Integrated pest management and food security. Dwight D. Eisenhower School for National Security and Resource Strategy - NC State team visit. February 27, 2014. Louws, F.J. 2013. Integrated management of strawberry and tomato soilborne diseases. International Congress of Plant Pathology. August 27 2013. Beijing China. Louws, F.J. Integrated Management of Soilborne Diseases of Field Grown Tomato and Strawberry. IPM2: 10thconference of the European Foundation of Plant Pathology. October 4, 2012. Louws, F.J. Integrated Disease Management: From Practice to Science and Back Again. Dept Plant Science. University of Arizona. December 6, 2011. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? An immediate short term goal of our work was to enable growers to transition to economically and technically viable non-ozone depleting fumigants. This was accomplished by collaborative efforts through a stakeholder-driven, multi-state and interdisciplinary program that linked novel research efforts and emerging knowledge to extension, educational and on-farm research (OFR) efforts to document efficacy and use of methyl bromide alternatives. During the life of this project, the southeast region witnessed a dramatic change in fumigant use patterns with 86% of growers using methyl bromide (MeBr) in the fall of 2011 to 100% complete transition away from MeBr by 2013. The fall of 2012 and 2013 was a critical transition time for growers and years of research-based data and OFR enabled most growers to transition smoothly. Our team interacted with fumigation businesses and growers to problem solve issues in a proactive and reactive way (if specific problems arose). The industry switched primarily to the use of PicClor 60 (chloropicrin 59.6% + 1,3-dichloropropene 39.0%) and our 2011 - 2014 fumigation experiments affirmed this product generated yields comparable to MeBr when used correctly. The project also sought to develop and/or implement other chemical-based tactics or non-chemical-based tactics extendable in the near term to manage soilborne pests and improve crop performance. This work began with previous funding but was extended for one more year of data (2011-2012 season). The core hypothesis was that novel and registered chemistry and technologies could play an important role in future non-fumigant production systems to suppress diseases and weeds. We used fungicides targeted for the known soilborne pathogens based on knowledge about the biology and ecology of the pathogens and crop phenology. Some of the programs offered yield benefits (e.g. use of Abound and/or Switch at planting; Ridomil drip applications in the fall and at early spring root growth, additional drip applications of Abound at first to full bloom) superior to the non-treated control but none performed as well as the fumigants. Therefore we support our previous conclusion that use of fungicide + herbicide programs are not a recommended practice for routine use to manage soilborne pests but may offer limited benefits when growers are not able to fumigate due to weather, time constraints, or regulatory restrictions. In the medium to long-term, our vision is to enable growers to adapt to economically and technically viable biologically-based systems to complement fumigant and chemical inputs or to supplant them. In this work we further detailed the diversity and dynamics of soilborne strawberry root and crown rot pathogens (black root rot complex; BRR) and of strawberry-associated beneficial organisms. We also emphasized work on soil amendments and farming systems research that included anaerobic soil disinfestation (ASD), mustard meal (M) amendments and the integrated use of cover crops (CC) and compost. In one project we surveyed, isolated and identified beneficial microorganisms (biological control agents; BCAs) present in the rhizosphere and endosphere of Fragaria virginiana (Mountain strawberry) and cultivated strawberry plants (F. x ananassa) from multiple regions of the US. The diversity of pathogenic fungi as well as bacteria and fungi populations differed in each plant source. Despite the presence of pathogens on roots, soil and plants, no disease symptoms were found on wild strawberries. Over 350 potential BCAs were obtained and these were narrowed down to a workable number based on multiple criteria and assays. Efficacy experiments where done under controlled conditions using F. ananassa var. Chandler or diploid seedlings and inoculating the soil at 0.5% (v/v) with Fusarium solani and Rhizoctonia solani. Selected BCAs decreased BRR severity (p ≥ 0.05) and/or combinations increased plant growth, especially using a combination of BCA fungi and bacteria. The hypothesis that wild strawberries may be a repository for BCA organisms was supported and additional work is needed to optimize the use of these BCAs as a component of integrated disease management systems for strawberry BRR. We also further documented the diversity and dynamics of major pathogen groups e.g. Pythium irregular, one of the causal agents of BRR. Soil and root samples were collected in TN and NC before setting up the experiment, when cover crops were harvested, at strawberry transplanting, one month after transplanting, at peak blooming and at peak harvest. DNA was extracted from soil and roots and qPCR analysis was performed on each sample. Population dynamics in soil varied according to the phenological stage of strawberry plants, reaching the lowest titre at peak blooming. Some treatments increased and others decreased root colonization levels. For example, MeBr and CC suppressed Pythium whereas ASD increased colonization of root tissue. Understanding the dynamics of the various pathogens associated with BRR should lead to better management strategies of the disease. Parallel work was done with Fusarium, Rhizoctonia and Trichoderma species associated with strawberry roots. On an OFR project, 'Benecia' plants on land with a long history of strawberry production were severely stunted, with 16% plant death due to BRR, the first case we have seen where BRR kills plants. Plots on "new land" immediately adjacent were dramatically healthier (4% death). Through OFR in TN, a highly labile source of carbon was used (dried molasses) and anaerobic conditions were achieved based on soil probe measurements. The ASD plant vigor and plant dry weight values were similar to ratings for plants in the MeBr and Pic60 plots and these were superior to values in the control plots, where plants were clearly stunted. At harvest, control plants had severe BRR symptoms and root rot severity ratings were significantly higher in the control plots. The ASD resulted in modest BRR symptoms and MeBr treated soils had the best root systems. Microbial community analysis was performed e.g. ASD resulted in the highest respiration rates; potential labile carbon tended to be highest in the control and ASD plots compared to the fumigated plots; microbial biomass carbon and nitrogen followed a similar pattern and a high rate of colonization in strawberry roots by arbuscular mycorrhiza fungi was observed and was highest in plants from the ASD and non-treated plots. Pic60 dramatically decreased Pythium colonization of roots and all treatments suppressed Fusarium colonization. Rhizoctonia and Trichoderma populations did not appear to be impacted by soil treatments. In TN research station trials, plants treated with Basamid tended to have the highest yields but biofumigation treatment with deoiled MM and ASD with molasses generated numerically lower but statistically similar yields and all were superior to the non-treated controls. In NC, four experiments were conducted. As an example of outcomes, in one trial 2012-2013, Pic-Clor 60 tended to have the highest yield. The ASD and CC (seeded end of June/early July) + compost systems were statistically similar to the Pic-Clor system. The MeBr plots tended to yield lower. The combination of CC+compost tended to increase yield and was significantly greater than the untreated control whereas each input alone did not offer an advantage. The MM system did not offer a benefit in this trial. In the following season (2013-2104), ASD, MM and Pic-Clor 60 treatments all generated similar yields; ASD was numerically the greatest. This was the second year with the same treatments in each plot. In this year, the CC+compost and CC or compost alone tended to perform less well and were not significantly different than the non-treated plots. These data highlight that ASD, MM and cover crop + compost systems are viable methods to suppress diseases and/or enhance yield but do require knowledgeable management.

Publications

  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Rysin, O., McWhirt, G. Fernandez, F.J. Louws and M.Schroeder-Moreno. 2015. Economic viability and environmental impact assessment of three different strawberry production systems in Southeastern United States. HortTechnology 25: 585-594.
  • Type: Journal Articles Status: Under Review Year Published: 2016 Citation: A. Torres-Barrag�n, P.C. Tran, C. Arellano and F.J. Louws. 2016. Biodiversity of cultural fungi and bacteria associated with wild and cultivated strawberry. Under review.
  • Type: Journal Articles Status: Under Review Year Published: 2016 Citation: A. Torres-Barrag�n, J. Sun, H. Whittington, J. Driver, C. Arellano and F.J. Louws. 20XX. Population dynamics of Pythium irregulare as impacted by soil treatments in strawberry production systems.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Louws, F.J. 2015. Integrated management of soilborne pathogens of tomato and strawberry: Local solutions and global benefits. The 8th International IPM Symposium, "IPM: Solutions for a Changing World". Abstr P159. http://www.ipmcenters.org/ipmsymposium15/Documents/ IPM_2015_Proceedings-final.pdf
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Torres-Barragan, A.; H.D. Whittington, J. Sun, J. Driver and F.J. Louws. 2014. Population dynamics of Pythium irregulare sensu stricto under different agronomic conditions. Phytopathology 104:S317.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Liu, B., Sun, J., Peeden, K., Driver, J., and Louws, F.J. 2011. Fumigation and fungicide effects and qualitative and quantitative analysis of Pythium, Fusarium and Rhizoctonia on strawberry roots. Phytopathology 101:S108.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2011 Citation: Torres-Barragan, A., Tran, P., Peeden, K.A., and Louws, F.J. 2011. Micro-biota associated with wild and cultivated strawberry and their potential use as biological control agents for strawberry black root rot. Phytopathology 101:S178.
  • Type: Websites Status: Published Year Published: 2014 Citation: Strawberry Diagnostic key: diagnosis.ces.ncsu.edu/strawberry
  • Type: Other Status: Published Year Published: 2014 Citation: Louws, F.J. 2015. Black root rot of strawberry. http://content.ces.ncsu.edu/black-root-rot-of-strawberry-1
  • Type: Other Status: Published Year Published: 2014 Citation: Louws, F.J. and G. Ridge. 2015. Phytophthora crown rot of strawberry. http://content.ces.ncsu.edu/phytophthora-crown-rot-of-strawberry
  • Type: Other Status: Published Year Published: 2014 Citation: Louws, F.J. and G. Ridge. 2015. Anthracnose crown rot of strawberry. http://content.ces.ncsu.edu/anthracnose-crown-rot-of-strawberry
  • Type: Other Status: Published Year Published: 2013 Citation: Louws, F.J. 2013. Preparing for the fall without methyl bromide. Strawberry Grower. July-August, 2013 vol. 20 NO. 6 pg.11-12.
  • Type: Other Status: Published Year Published: 2011 Citation: Louws, F.J. 2011. Changing face of fumigation. Growing Produce. Nov 15. http://www.growingproduce.com/article/24165/changing-face-of-fumigation
  • Type: Other Status: Published Year Published: 2011 Citation: Louws, F.J. 2011. The changing face of fumigation and options to grow strawberries without fumigants. Small Fruit News 11(4):6-9; The Strawberry Grower 18(7):7-11.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Wheeler, J., D. Deyton, D. Butler, F.J. Louws and C. Sams. 2015. Impacts of biofumigation and anaerobic soil disinfestation on strawberry plant nutrition and fruit quality. ASHS Abstracts 2015.