Source: IOWA STATE UNIVERSITY submitted to NRP
RESILIENT SYSTEMS FOR SUSTAINABLE MANAGEMENT OF CUCURBIT CROPS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1020780
Grant No.
2019-51300-30248
Cumulative Award Amt.
$2,000,000.00
Proposal No.
2019-03098
Multistate No.
(N/A)
Project Start Date
Sep 1, 2019
Project End Date
Feb 29, 2024
Grant Year
2019
Program Code
[113.A]- Organic Agriculture Research & Extension Initiative
Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011
Performing Department
Plant Pathology-EXT
Non Technical Summary
Our goal is to validate two innovative strategies that will enable organic cucurbit-crop growers to suppress insect pests, diseases, and weeds while achieving consistently high marketable yields. Cucumber beetles and bacterial wilt, squash bug and cucurbit yellow vine disease, squash vine borer, powdery mildew, downy mildew, and weeds cost growers >$100 million annually and limit organic marketing opportunities. Three years of field experiments and on-farm trials with muskmelon and acorn squash in Kentucky, Iowa, and New York will optimize mesotunnels - season-long tunnels that can sharply increase marketable yield and suppress pests and diseases - to control weeds, build soil quality with living mulches, and achieve efficient pollination (Objective 1). Concurrently, we will develop biological controls to suppress bacterial and fungal diseases, both as a companion strategy to mesotunnels and as a stand-alone practice (Objective 2). Growers will provide continuous feedback via an Advisory Panel, grower surveys and listening sessions, and on-farm cooperator trials. We will use results of the field experiments to calculate profitability in the South, Midwest, and Northeast, and grower viewpoints will inform rates of adoption of these new tools (Objective 3). A multi-strategy outreach program will reach 7,000 cucurbit growers throughout these regions (Objective 4). The project directly addresses four OREI priorities: trialing innovative practices that can mitigate pest and disease damage (Priority 1), comparing costs and profitability of new management approaches with existing practices (Priority 2), counducting on-farm trials to insure adaptability of new approaches (Priority 6), and conserving beneficials and improving soil quality (Priority 7).
Animal Health Component
50%
Research Effort Categories
Basic
30%
Applied
50%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
10201991060100%
Knowledge Area
102 - Soil, Plant, Water, Nutrient Relationships;

Subject Of Investigation
0199 - Soil and land, general;

Field Of Science
1060 - Biology (whole systems);
Goals / Objectives
A complex of pests and diseases are acutely challenging for organic cucurbit vegetable growers, as they lack access to management tactics that provide reliable protection against crop failure. Inconsistency of organic marketable yields limits profit opportunities at all levels from direct on-farm sales to wholesaling. Organic cucurbit growers urgently need pest and disease management systems that will reliably deliver high marketable yields in order to capitalize on the expanding market for organic produce (see Section 1.2, page 2, and Section 1.5, page 4).The long-term goals of the proposed project are to:1) Control major insect and disease pests all season to ensure consistently high marketable yield and profitability of organic muskmelon and winter squash production.2) Protect pollinators and natural-enemy insects by eliminating the need for insecticide use.3) Suppress weeds while enhancing soil health attributes.4) Gain additional flexibility in disease management through diverse physical and biological control options.
Project Methods
Objective 1. We will conduct three annual field trials on certified organic land at the Iowa State University (ISU) Horticulture Research Station near Gilbert, IA, the University of Kentucky (UK) Organic Farming Unit in Lexington, KY, and the Cornell University AgriTech's Gates West Research Farm in Geneva, NY. We will assess weed control, pollinator efficiency, and pest/disease control in separate field experiments on muskmelon (cv. Athena) and acorn squash (cv. Table Ace). Experimental design will be a randomized complete block with four replications per treatment. The weed control experiment (Task 1.1) will include a living mulch, a shredded crop residue control, and a bare ground control. The pollination optimization experiment (Task 1.2) hypothesizes that in our 200-ft-long subplots, stocking two bumble bee (Bombus impatiens) colonies will increase pollination and marketable yield across an entire mesotunnel, whereas stocking a single colony will result in diminished pollination rates with increasing distance from the colony. The pest and disease control experiment (Task 1.3) will monitor for insect pests (cucumber beetles, squash bugs, squash vine borers, and aphids) and bacterial diseases (bacterial wilt and CYVD) to evaluate the effectiveness of the mesotunnels for excluding insect pests and their associated pathogens.Objective 2. A primary screen will evaluate candidate biocontrol agents for activity against Erwinia tracheiphila and Serratia marcescens. Candidates will include bacteria that trigger induced systemic resistance (ISR) in cucurbits, bacteria with biocontrol activity against similar diseases in other crops, and mixtures of bacterial pathogen-specific phages (viruses that attack bacteria). We will use a rapid cucurbit seedling assay as a primary screen in growth chambers to apply suspensions of the biocontrol candidates to 2-week-old muskmelon and acorn squash seedlings, with wounding, prior to inoculation with the bacterial pathogens, and determine efficacy based on disease symptom severity across at least 20 replicate plants in each of at least three replicate experiments. Bacterial agents active in biocontrol against either pathogen will be examined in a similar assay for control of powdery mildew (Podosphaera xanthii) or downy mildew (Pseudoperonospora cubensis). Biocontrol agents will be selected for further screening if they reduce the incidence or severity of any of these diseases. Agents selected in the primary screen in the laboratory (Task 2.1) will be examined in greenhouse studies (Task 2.2). We will identify the minimal dose required for effective control against the target pathogens, and the biocontrol efficacy provided by mixtures of the agents to explore opportunities for synergy.During the growing seasons of Years 2 and 3, we will field test the biocontrol agents that exhibit significant protection against disease in the greenhouse (Task 2.3). A randomized complete block design will be used with shredded mulch for weed control. Treatments will be: Up to four candidate biocontrol agents, each applied in a separate mesotunnel;?a water-inoculated mesotunnel control; and a non-mesotunnel control (no biocontrol agents).In Years 2 and 3, the field tests will be performed at ISU's Horticulture Research Station, and in Year 3, in Kentucky and New York (Task 2.4). In Year 2, the biocontrol agents will be applied as foliar sprays immediately before transplantation. In Year 3, we will use the optimal application and formulation approaches identified in Task 2.2. Populations of bacterial biocontrol agents will be estimated by plate counts. We will assess yield and produce quality at harvest.Objective 3.We will use economic and social theories and methods to: compare the profitability and cost effectiveness of mesotunnel systems and biological control approaches, alone and in combination, with current organic systems for muskmelon and acorn squash production; understand growers' perceptions and experiences with pest and disease threats, high-priority concerns associated with cucurbit crop production, cautions and concerns about mesotunnels and biocontrols, and determine knowledge, skills, and economic, social, and psychological barriers to and enabling factors for adopting these technologies; and ensure grower-scientist collaboration and knowledge exchanges to produce useable science and technologies.We will use mixed methods including partial budget analysis, surveys, semi-structured multidisciplinary team discussion processes, listening sessions, and evaluative tools in concert with an external evaluator.Objective 4. We will expand our CoP website The Current Cucurbit[39], which uses short video clips to share the project's activities. The sote will increase to 2,000 page views per week by the end of Year 2.A twice-monthly blog will push the project's messages to Extension educators and stakeholders and drive traffic to the CoP website. Blog segments of 150 to 300 words will capsulize various aspects of project activities and link to resources on the CoP site and elsewhere. Availability of each blog will be tweeted to followers throughout the eastern half of the U.S.We will produce 30 YouTube video segments, and solicit feedback twice per year via online reactionnaire surveys. Two Year 3 webinars will invite participation from the Advisory Panel as well as extension educators and crop advisers throughout the eastern U.S., and be posted to the national eOrganic website and the project website. There will be 3 on-farm demonstration trials per state annually. Participants will select one or more trials using mesotunnels andd/or biological controls. In Year 3, the PIs will prepare and upload a manual for organic cucurbit growers in the South, Midwest, and Northeast on using mesotunnels and biological control.

Progress 09/01/19 to 02/29/24

Outputs
Target Audience:Commercial growers of cucurbit crops in the central and eastern U.S. Changes/Problems:The COVID-19 pandemic caused significant delays in field and laboratory research by preventingaccess to these sites for as long as one year (2020-2021) in some cases. For example, replicated field experiments in NY (Cornell University) were prohibited during the first field season (2020). The pandemic also disrupted plans for in-person annual project meetings and in-person grower interviews. Fortunately, the timely availabilityof videoconferencing technology allowed us to switch to monthly project meetings via Zoom and to substitute phone interviews for in-person grower interviews. Overall, the project team demonstrated patience, resilience, and a can-do attitude in overcoming these early-project limitations. Objective 1 weed controlexperiments using the cereal grass teff (Eragrostis tef)as a living mulch in IA and KY were modified in years 2 and 3. A singlemowing of teff in the alley between crop rows was instituted as cucurbit crop flowering began - about 3 weeks after teff was seeded. This modification was madein order to suppress teff's competition with the cucurbit crop, which had resulted in yield loss duringyear 1. Mowing teffenabled us to achieve excellent weed control with this living mulch during the critical early season for weed control (first 3 weeks after transplanting cucurbit seedlings) but avoided suppressing marketable yield of the cucurbit crop. We learned that timing of mowing teff was important; mowing the alleys 3 weeks after seeding teffavoided damage to runners of cucurbit crops while achieving durable weed control. We recommend that future field experiments be undertaken to optimize thetiming of teff mowing according to the specific region and cucurbit crop. Another learning experience with teff concerned germination; seeding is done at about the same time as the cucurbit crop is transplanted, but dry weather can prevent or delaygermination and emergence of teff. The take-home points for growers, as emphasized in the Growers Manual, are to make sure there is good seed-soil contact when sowing teffand to provide irrigation after sowing if they are seeding into dry soil with minimal rain in the forecast. During the 4th yearof the project, an ISU graduate student on the project, Kephas Mphande, was contacted by a giant-pumpkin grower in Connecticut regarding a CYVD outbreak (the contact occurreddue to our project's outreach activities).At the time, only squash bugs (Anasa tristis) were known to spread the CYVD pathogen (the bacteriumSerratia marcescens). However, the grower had seen only striped cucumber beetles in his field; no squash bugs at all. When Kephas conducted a PCR assay for this pathogen on cucumber beetles from the giant-pumpkin field, the results were positive. Thisdiscovery led to lab experiments in which Kephasshowed conclusively that cucumber beetles can spread the CYVD pathogen to cucurbit plants. This discovery is a major advance in knowledge of CYVD ecology and provides critical new information to inform practical control of this major emerging disease ofcucurbits. What opportunities for training and professional development has the project provided?The project provided training and professional development for 8 graduate students, 5technical staff members, and 18 undergraduate research assistants. For graduate students, training opportunities included field experiment design, conduct, data analysis, and preparation of manuscripts for publication; authorship of outreach products including blog posts, YouTube video clips, and podcast interviews; presentations at grower field days; authorship of extension bulletins and infographics; design, conduct, and data analysis for small-and large-scale grower surveys; and preparation of posters and oral presentations at state, regional, and national grower and scientific conferences. Technical staff gained experience with project planning and coordination, data analysis, preparation and publication of manuscripts and online case studies, and preparation of poster and oral presentations at grower and scientific conferences. Undergraduate research assistants gained experience in field research design, conduct, and data analysis; organization and conduct of phone surveys of cooperating growers; and co-authorship of outreach and research publications. How have the results been disseminated to communities of interest?The mainoutreach product for target growers was the Growers Manual outlining practical take-homemessages for cucurbit growers from our team's multi-year experiences with mesotunnels for organic cucurbits in experimental and on-farm contexts. 100 print copies were produced and distributed to growers in each participating state, and the Growers Manual is available onlineat: https://www.cucurbit.plantpath.iastate.edu/growers-manual. All additionaloutreach products and presentations are summarized under Products, Other Products, and the project's External Evaluation (appended to this final report). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The projectprovided substantialnear-term and intermediate-term value toUS cucurbit growers and society as a whole. Near-term applicationof field trials and economic analysis (Objectives 1 and 3).Mesotunnels - a novel field production system using breathable mesh-type nylon covers as a season-long or nearly season-long barrier to pest insects and the bacterial disease they carry - kept out major economic pests/disease vectors (cucumber beetles and squash bugs) in three years of IA, KY, and NY field experiments. They alsosuppressed two major bacterial diseasesof cucurbit crops - bacterial wilt and cucurbit yellow vine disease. The result was effective pest and bacterial disease control - and often higher marketable yield - with far fewerpesticide sprays than other production systems. Marketable yield ofstrategies to ensure crop pollination and weed control undermesotunnels varied by crop and state. For example,placinghives of purchased bumble beesunder mesotunnels to ensure pollination increasedmarketable yield and profit potential of muskmelon in IAbut not in KY or NY. Also, seedingthe drought-tolerant grass teff as a living mulch between crop rows controlled weeds effectively in KY and IA but was unsuited for use in NY. Economic analysis provided convincing evidence that 1) mesotunnel systems for organic winter squash production in KY were more profitablethan non-covered, pesticide-dependent strategies, and 2) for organic muskmelon in IA, a full-season mesotunnelstrategy usingpurchased bees wasmore profitable than openingthe tunnelstemporarily to permit pollination by ambient bee populations. In most KY and NY field trials, mesotunnels also suppressed a major fungal disease, powdery mildew, more effectively than non-covered control treatments. Intermediate-term applications of fundamental discoveries (Objective 2).Discoveries in IAlaboratory and growth-chamber trialshave strong potential to pay off for growers within 5 years. First, the new bioassay we developed for CYVD in squash means that crop breeders can now develop CYVD-resistant varieties. Second, we showed for the first time that cucumber beetles, as well as squash bugs, can spread the CYVD bacterium - a novelinsight that will have majorimplications for disease-management strategies in the field. Third, we identified genes in the CYVD bacterium that contribute to pathogenicity - another important advance toward creating resistant varieties. Finally, we identified, for the first time, several bacteriophages and bacteria that can suppress bacterial wilt when sprayed onto muskmelon plants - an advancethat opens the door to practical biological control of this dreadeddisease. Outreach (Objectives 3 and 4).The project's extensiveportfolio of outreach products - blogs, videos, podcasts, webinars, posters, and aGrowers Manual - is capsulized in the project website, The Current Cucurbit (www.cucurbit.iastate.edu). This website will continue to be accessible for 5 years after the project period as part of the North Central IPM Center's website. Numerous field days and grower conference presentations also shared the project's findings widely. Results of our annual phone surveysof cooperating commercial growers and year 3 survey of over 300 cucurbit growers in the Midwest and East make it clear that many growers are interested intrying mesotunnel systems and applying the new scientific insights generated by the project. Benefits to society at large.As a result of this project, organicgrowers of cucurbit cropsin the Midwest and East have gained promising new options for consistently profitable production. Byshowingthat mesotunnelscan protect cucurbit crops for all or nearly all of the production season, we demonstrated a practical, economically viable way to suppress insect pests and the diseases they carry with far less need for chemical insecticides. Mesotunnels can also protect crops from damage by hail and wind. These systems can help ensure consistent marketable yieldand thereby open new market opportunities for organic produce. Growers and their neighbors can also benefit by using living mulches like teff, whichbuild soil organic matter and prevent erosion. Mesotunnels can also safeguard thehealth of farm workers and consumersby reducing or eliminating pesticide residues on purchased produce.

Publications

  • Type: Journal Articles Status: Published Year Published: 2024 Citation: Mphande, K., Badilla-Arias, S., Cheng, N., Gonz�lez-Acu�a, J., Nair, A., Zhang, W., and Gleason, M.L. 2024. Evaluating pollination and weed control strategies under mesotunnel systems for organic muskmelon production in Iowa. HortTechnology 34:265-279. DOI: https://doi.org/10.21273/HORTTECH05379-23
  • Type: Journal Articles Status: Published Year Published: 2024 Citation: Mphande, K., Beattie, G.A,, and Gleason, M.L. 2024. First Report of Cucurbit Yellow Vine Disease Caused by Serratia marcescens on Cucurbit Crops in Iowa. Plant Disease doi.org/10.1094/PDIS-12-23-2716-PDN.
  • Type: Journal Articles Status: Submitted Year Published: 2024 Citation: Mphande, K., Beattie, G.A., and Gleason, M.L. 2024. A quantitative in vivo pathogenicity assay for cucurbit yellow vine disease caused by Serratia marcescens. Plant Disease. Submitted.
  • Type: Journal Articles Status: Other Year Published: 2024 Citation: Mphande, K., LaSarre, B., Gleason, M.L., Matteen, Z.T., Little, E.L., and Beattie, G.A. 2024. Tissue localization and role of fimbriae in the pathogenicity of Serratia marcescens, a unique phloem pathogen of cucurbits. Phytopathology: in preparation.
  • Type: Journal Articles Status: Other Year Published: 2024 Citation: Mphande, K., LaSarre, B., Badilla-Arias, S., Gleason, M.L., and Beattie, G.A. 2024. Cucumber beetles serve as alternative vectors to squash bugs for the phloem-associated pathogen Serratia marcescens on squash. Phytopathology: in preparation.
  • Type: Journal Articles Status: Other Year Published: 2024 Citation: Badilla-Arias, S., Mphande, K., Cheng, N., Gonz�lez-Acu�a, J., Nair, A., Zhang, W., and Gleason, M.L. 2024. Mesotunnels for organic acorn squash production in Iowa: field evaluation of pollination and weed control strategies. PhytoFrontiers: in preparation.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Badilla-Arias, S., Mphande, K., and Gleason, M.L. 2024. Managing teff as a living mulch for organic acorn squash and muskmelon in mesotunnel systems. Iowa Specialty Producers Conference, Ankeny, Iowa, January 8, 2024.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Badilla-Arias, S., Gleason, M.L., and Beattie, G.A. 2024. Enterobacter cloacae and a bacteriophage of the pathogen Erwinia tracheiphila as biocontrol agents of cucurbit bacterial wilt of muskmelon. Third International Congress of Biological Control (ICBC3), San Jos�, Costa Rica, June 24-27, 2024.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Badilla-Arias, S., Gleason, M.L., and Beattie, G.A. 2024. Combating cucurbit bacterial wilt: Enterobacter cloacae and the bacteriophage FBB1 as promising biocontrol candidates. ICPPB & Biocontrol 2024, Blacksburg, Virginia, July 7-12, 2024.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Tong, J., Zhang, W., Dentzman, K., and Gleason, M.L. 2024. What Drives Organic Cucurbit Growers to Adopt Mesotunnel Row Covers? An Application of Technology Acceptance Model. Agriculture, Food & Human Values Society (AFHVS) and the Association for the Study of Food and Society (ASFS) Conference, June 5-8, Syracuse, NY.


Progress 09/01/19 to 02/28/24

Outputs
Target Audience:Commercial growers of cucurbit crops in the central and eastern U.S. Changes/Problems:The COVID-19 pandemic caused significant delays in field and laboratory research by preventingaccess to these sites for as long as one year (2020-2021) in some cases. For example, replicated field experiments in NY (Cornell University) were prohibited during the first field season (2020). The pandemic also disrupted plans for in-person annual project meetings and in-person grower interviews. Fortunately, the timely availabilityof videoconferencing technology allowed us to switch to monthly project meetings via Zoom and to substitute phone interviews for in-person grower interviews. Overall, the project team demonstrated patience, resilience, and a can-do attitude in overcoming these early-project limitations. Objective 1 weed controlexperiments using the cereal grass teff (Eragrostis tef)as a living mulch in IA and KY were modified in years 2 and 3. A singlemowing of teff in the alley between crop rows was instituted as cucurbit crop flowering began - about 3 weeks after teff was seeded. This modification was madein order to suppress teff's competition with the cucurbit crop, which had resulted in yield loss duringyear 1. Mowing teffenabled us to achieve excellent weed control with this living mulch during the critical early season for weed control (first 3 weeks after transplanting cucurbit seedlings) but avoided suppressing marketable yield of the cucurbit crop. We learned that timing of mowing teff was important; mowing the alleys 3 weeks after seeding teffavoided damage to runners of cucurbit crops while achieving durable weed control. We recommend that future field experiments be undertaken to optimize thetiming of teff mowing according to the specific region and cucurbit crop. Another learning experience with teff concerned germination; seeding is done at about the same time as the cucurbit crop is transplanted, but dry weather can prevent or delaygermination and emergence of teff. The take-home points for growers, as emphasized in the Growers Manual, are to make sure there is good seed-soil contact when sowing teffand to provide irrigation after sowing if they are seeding into dry soil with minimal rain in the forecast. During the 4th yearof the project, an ISU graduate student on the project, Kephas Mphande, was contacted by a giant-pumpkin grower in Connecticut regarding a CYVD outbreak (the contact occurreddue to our project's outreach activities).At the time, only squash bugs (Anasa tristis) were known to spread the CYVD pathogen (the bacteriumSerratia marcescens). However, the grower had seen only striped cucumber beetles in his field; no squash bugs at all. When Kephas conducted a PCR assay for this pathogen on cucumber beetles from the giant-pumpkin field, the results were positive. Thisdiscovery led to lab experiments in which Kephasshowed conclusively that cucumber beetles can spread the CYVD pathogen to cucurbit plants. This discovery is a major advance in knowledge of CYVD ecology and provides critical new information to inform practical control of this major emerging disease ofcucurbits. What opportunities for training and professional development has the project provided?The project provided training and professional development for 8 graduate students, 5technical staff members, and 18 undergraduate research assistants. For graduate students, training opportunities included field experiment design, conduct, data analysis, and preparation of manuscripts for publication; authorship of outreach products including blog posts, YouTube video clips, and podcast interviews; presentations at grower field days; authorship of extension bulletins and infographics; design, conduct, and data analysis for small-and large-scale grower surveys; and preparation of posters and oral presentations at state, regional, and national grower and scientific conferences. Technical staff gained experience with project planning and coordination, data analysis, preparation and publication of manuscripts and online case studies, and preparation of poster and oral presentations at grower and scientific conferences. Undergraduate research assistants gained experience in field research design, conduct, and data analysis; organization and conduct of phone surveys of cooperating growers; and co-authorship of outreach and research publications. How have the results been disseminated to communities of interest?The mainoutreach product for target growers was the Growers Manual outlining practical take-homemessages for cucurbit growers from our team's multi-year experiences with mesotunnels for organic cucurbits in experimental and on-farm contexts. 100 print copies were produced and distributed to growers in each participating state, and the Growers Manual is available onlineat: https://www.cucurbit.plantpath.iastate.edu/growers-manual. All additionaloutreach products and presentations are summarized under Products, Other Products, and the project's External Evaluation (appended to this final report). What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The projectprovided substantialnear-term and intermediate-term value toUS cucurbit growers and society as a whole. Near-term applicationof field trials and economic analysis (Objectives 1 and 3).Mesotunnels - a novel field production system using breathable mesh-type nylon covers as a season-long or nearly season-long barrier to pest insects and the bacterial disease they carry - kept out major economic pests/disease vectors (cucumber beetles and squash bugs) in three years of IA, KY, and NY field experiments. They alsosuppressed two major bacterial diseasesof cucurbit crops - bacterial wilt and cucurbit yellow vine disease. The result was effective pest and bacterial disease control - and often higher marketable yield - with far fewerpesticide sprays than other production systems. Marketable yield ofstrategies to ensure crop pollination and weed control undermesotunnels varied by crop and state. For example,placinghives of purchased bumble beesunder mesotunnels to ensure pollination increasedmarketable yield and profit potential of muskmelon in IAbut not in KY or NY. Also, seedingthe drought-tolerant grass teff as a living mulch between crop rows controlled weeds effectively in KY and IA but was unsuited for use in NY. Economic analysis provided convincing evidence that 1) mesotunnel systems for organic winter squash production in KY were more profitablethan non-covered, pesticide-dependent strategies, and 2) for organic muskmelon in IA, a full-season mesotunnelstrategy usingpurchased bees wasmore profitable than openingthe tunnelstemporarily to permit pollination by ambient bee populations. In most KY and NY field trials, mesotunnels also suppressed a major fungal disease, powdery mildew, more effectively than non-covered control treatments. Intermediate-term applications of fundamental discoveries (Objective 2).Discoveries in IAlaboratory and growth-chamber trialshave strong potential to pay off for growers within 5 years. First, the new bioassay we developed for CYVD in squash means that crop breeders can now develop CYVD-resistant varieties. Second, we showed for the first time that cucumber beetles, as well as squash bugs, can spread the CYVD bacterium - a novelinsight that will have majorimplications for disease-management strategies in the field. Third, we identified genes in the CYVD bacterium that contribute to pathogenicity - another important advance toward creating resistant varieties. Finally, we identified, for the first time, several bacteriophages and bacteria that can suppress bacterial wilt when sprayed onto muskmelon plants - an advancethat opens the door to practical biological control of this dreadeddisease. Outreach (Objectives 3 and 4).The project's extensiveportfolio of outreach products - blogs, videos, podcasts, webinars, posters, and aGrowers Manual - is capsulized in the project website, The Current Cucurbit (www.cucurbit.iastate.edu). This website will continue to be accessible for 5 years after the project period as part of the North Central IPM Center's website. Numerous field days and grower conference presentations also shared the project's findings widely. Results of our annual phone surveysof cooperating commercial growers and year 3 survey of over 300 cucurbit growers in the Midwest and East make it clear that many growers are interested intrying mesotunnel systems and applying the new scientific insights generated by the project. Benefits to society at large.As a result of this project, organicgrowers of cucurbit cropsin the Midwest and East have gained promising new options for consistently profitable production. Byshowingthat mesotunnelscan protect cucurbit crops for all or nearly all of the production season, we demonstrated a practical, economically viable way to suppress insect pests and the diseases they carry with far less need for chemical insecticides. Mesotunnels can also protect crops from damage by hail and wind. These systems can help ensure consistent marketable yieldand thereby open new market opportunities for organic produce. Growers and their neighbors can also benefit by using living mulches like teff, whichbuild soil organic matter and prevent erosion. Mesotunnels can also safeguard thehealth of farm workers and consumersby reducing or eliminating pesticide residues on purchased produce.

Publications

  • Type: Journal Articles Status: Published Year Published: 2024 Citation: Mphande, K., Badilla-Arias, S., Cheng, N., Gonz�lez-Acu�a, J., Nair, A., Zhang, W., and Gleason, M.L. 2024. Evaluating pollination and weed control strategies under mesotunnel systems for organic muskmelon production in Iowa. HortTechnology 34:265-279. DOI: https://doi.org/10.21273/HORTTECH05379-23
  • Type: Journal Articles Status: Published Year Published: 2024 Citation: Mphande, K., Beattie, G.A,, and Gleason, M.L. 2024. First Report of Cucurbit Yellow Vine Disease Caused by Serratia marcescens on Cucurbit Crops in Iowa. Plant Disease doi.org/10.1094/PDIS-12-23-2716-PDN.
  • Type: Journal Articles Status: Submitted Year Published: 2024 Citation: Mphande, K., Beattie, G.A., and Gleason, M.L. 2024. A quantitative in vivo pathogenicity assay for cucurbit yellow vine disease caused by Serratia marcescens. Plant Disease. Submitted.
  • Type: Journal Articles Status: Other Year Published: 2024 Citation: Mphande, K., LaSarre, B., Gleason, M.L., Matteen, Z.T., Little, E.L., and Beattie, G.A. 2024. Tissue localization and role of fimbriae in the pathogenicity of Serratia marcescens, a unique phloem pathogen of cucurbits. Phytopathology: in preparation.
  • Type: Journal Articles Status: Other Year Published: 2024 Citation: Mphande, K., LaSarre, B., Badilla-Arias, S., Gleason, M.L., and Beattie, G.A. 2024. Cucumber beetles serve as alternative vectors to squash bugs for the phloem-associated pathogen Serratia marcescens on squash. Phytopathology: in preparation.
  • Type: Journal Articles Status: Other Year Published: 2024 Citation: Badilla-Arias, S., Mphande, K., Cheng, N., Gonz�lez-Acu�a, J., Nair, A., Zhang, W., and Gleason, M.L. 2024. Mesotunnels for organic acorn squash production in Iowa: field evaluation of pollination and weed control strategies. PhytoFrontiers: in preparation.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Badilla-Arias, S., Mphande, K., and Gleason, M.L. 2024. Managing teff as a living mulch for organic acorn squash and muskmelon in mesotunnel systems. Iowa Specialty Producers Conference, Ankeny, Iowa, January 8, 2024.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Badilla-Arias, S., Gleason, M.L., and Beattie, G.A. 2024. Combating cucurbit bacterial wilt: Enterobacter cloacae and the bacteriophage FBB1 as promising biocontrol candidates. ICPPB & Biocontrol 2024, Blacksburg, Virginia, July 7-12, 2024.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Tong, J., Zhang, W., Dentzman, K., and Gleason, M.L. 2024. What Drives Organic Cucurbit Growers to Adopt Mesotunnel Row Covers? An Application of Technology Acceptance Model. Agriculture, Food & Human Values Society (AFHVS) and the Association for the Study of Food and Society (ASFS) Conference, June 5-8, Syracuse, NY.
  • Type: Journal Articles Status: Published Year Published: 2024 Citation: Fiske, K., Cheng, N., Kuesel, R., Zhang, W., Bessin, R., Williams, M.A., and Gonthier, D. 2024. Row covers limit pests and disease and increase profit in organic acorn squash. Frontiers in Sustainable Food Systems Volume 8. doi: 10.3389/fsufs.2024.1347924 Row covers limit pests and disease and increase profit in organic acorn squash
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2024 Citation: Badilla-Arias, S., Gleason, M.L., and Beattie, G.A. 2024. Enterobacter cloacae and a bacteriophage of the pathogen Erwinia tracheiphila as biocontrol agents of cucurbit bacterial wilt of muskmelon. Third International Congress of Biological Control (ICBC3), San Jos�, Costa Rica, June 24-27, 2024.


Progress 09/01/22 to 08/31/23

Outputs
Target Audience:Commercial growers of cucurbit vegetable crops in the U.S. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students trained: Sharon Badilla Kephas Mphande Kathleen Fiske Kaitlin Diggins Alexis Gauger Ryan Kuesel Research coordinators trained: Jose Gonzalez Kellie Damann Abigail Tikhtman Undergraduate research interns trained: Kaitlin Diggins Isabel Danicich Catherine Esparza Jessica Fischer Mateo Garcia Alexandra Guy Ben Morrison Mallory Sparks How have the results been disseminated to communities of interest? See Products section of this report. What do you plan to do during the next reporting period to accomplish the goals?Our final-year plans include: Publish 6 additional research papers based on project findings under Objectives 1, 2, and 3. Transition the project website, The Current Cucurbit (https://www.cucurbit.plantpath.iastate.edu), to North Central IPM Center website to ensure its outputs are accessible to all interested parties for an additional 5 years beyond the end of the project period. Prepare the final project report.

Impacts
What was accomplished under these goals? Year 4 was a no-cost extension year. Under Objective 1 (field trials to optimize mesotunnel use) we submitted two research manuscripts based on New York research. The manuscript on acorn squash, summarizing experiments evaluating alternatives to accomplish pollination and weed control under mesotunnels, was accepted pending revision by Plant Health Progress. The NY mesotunnel manuscript on muskmelon is in review with another journal. A third manuscript, from Iowa field trials on muskmelon, will be submitted to Plant Disease in December 2023; this manuscript includes an economic analysis of the field trials. A fourth manuscript, reporting findings of the Iowa acorn squash field trials in mesotunnels, is in preparation for submission to HortTechnology in April 2024. Objective 2 (laboratory research on the bacteria that cause cucurbit bacterial wilt and cucurbit yellow vine disease, aka CYVD) featured: i) development of the first quantitative pathogenicity assay for the CYVD bacterium, Serratia marcescens, which is a major step forward for resistance breeding; ii) discovery, using GFP labeling and microscopy, that S. marcescens invades through intercellular spaces adjoining the phloem (a major change from previously accepted dogma about how this pathogen attacks plants); iii) identification of genes in the CYVD bacterium associated with its abillity to infect plants; iv) the first experimental evidence that cucumber beetles - previously known to spread only the cucurbit bacterial wilt pathogen, Erwinia tracheiphila - can also spread the CYVD bacterium from plant to plant (a finding that has immense applications for practical control of CYVD); v) experimental proof that several biocontrol bacteria can also suppress cucurbit bacterial wilt; and vi) evidence that some of these biocontrol bacteria can suppresws bacterial wilt when applied as a spray, which is a major breakthrough toward making biological control practical as an alternative to sythetic chemical insecticides. Manuscripts reporting these important findings are in preparation. Objective 3 (socioeconomic analysis): we completed economic analysis of the Iowa field experiments and published a report summarizing findings of a national survey of cucurbit vegetable growers. Objective 4: We published a Growers Manual summarizing the key practical tips for using mesotunnels. See Products section of this REEport for details on Year 4 outputs.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Badilla Arias, S., Gleason, M.L., and Beattie, G.A. 2023. Screening for biocontrol agents of bacterial wilt of cucurbits. National meeting of American Phytopathological Society, Denver, Colorado, August 13-16, 2023.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Mphande, K., LaSarre, B., Gleason, M.L., and Beattie, G.A. 2023. Exploring the molecular mechanisms of pathogenicity and localization of Serratia marcescens, which causes cucurbit yellow vine disease. National meeting of American Phytopathological Society, Denver, Colorado, August 13-16, 2023.
  • Type: Other Status: Published Year Published: 2023 Citation: Cheng, N., Zhang, W., Gonzalez, J., and Gleason, M.L. 2023. Controlling Pests and Diseases Using Mesotunnels: Understanding Organic Cucurbit Crop Growers' Preferences and Choices. Report EB 05-2023, Charles H. Dyson School of Applied Economics and Management, Cornell University, June 2023.
  • Type: Other Status: Published Year Published: 2023 Citation: Gonzalez, J., Gonthier, D., Pethybridge, S., Bessin, R., Nair, A., Zhang, W., Cheng, N., Fiske, K., Gauger, A., Damann, K., Murphy, S., Badilla, S., Mphande, K., and Gleason, M. 2023. Mesotunnels for organic management of cucurbit pests and diseases: tips for growers. NCPA 038, North Central IPM Center. Bulletin NCPA 038, North Central IPM Center, University of Minnesota, St. Paul, MN. 8 pp.
  • Type: Websites Status: Published Year Published: 2023 Citation: The Current Cucurbit (project website). https://www.cucurbit.plantpath.iastate.edu/. ~1,200 visits in 2023.
  • Type: Journal Articles Status: Submitted Year Published: 2024 Citation: Mphande, K., Badilla-Arias, S., Cheng, N., Gonz�lez-Acu�a, J., Nair, A., Zhang, W., and Gleason, M.L. 2023. Evaluating pollination and weed control strategies under mesotunnel systems for organic muskmelon production in Iowa. HortTechnology: Submitted.
  • Type: Journal Articles Status: Under Review Year Published: 2023 Citation: Pethybridge, S., Damann, K., Murphy, S., Diggins, K.R., and Gleason, M.L. 2023. Evaluation of mesotunnels for organic muskmelon production in New York, USA. Renewable Agriculture and Food Systems: Accepted pending revision.
  • Type: Journal Articles Status: Accepted Year Published: 2023 Citation: Pethybridge, S.J., Damann, K., Murphy, S., Diggins K., and Gleason, M.L. Gleason. 2023. Optimizing Integrated Pest Management in Mesotunnels for Organic Acorn Squash in New York. Plant Health Progress: Accepted.
  • Type: Other Status: Published Year Published: 2023 Citation: Diggins, K., and Gonzalez, J. 2023. Cucurbit Grower Perceptions of Mesotunnel Systems: 2022 Grower Interview Findings. Power Point presentation, June 12, 2023. https://www.cucurbit.plantpath.iastate.edu/files/inline-files/diggins%202022%20Cooperator%20Perceptions%20summary%2010.23%20FULL.pdf.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Gonthier, D.J. 2023. Plastics-based protection systems in organic agriculture. Conference on Reducing Plastics Along the Entire Organic Supply Chain. The Organic Trade Association, Washington, DC. May 9, 2023. Oral presentation.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Gonthier, D. 2022. Pollination strategies for cucurbit crops under mesotunnels. Michigan State University & Great Lakes Fruit, Vegetable, & Farm Market Expo. Grand Rapids, MI (December 7, 2022). Oral presentation.


Progress 09/01/21 to 08/31/22

Outputs
Target Audience:The target audience for this project is commercial growers of cucurbit crops. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Kathleen Fiske, PhD candidate, Department of Entomology, University of Kentucky -Field research experience, mentoring of undergraduate research assistants, development of outreach materials (blog posts), and presentation of results at academic and grower's meetings. Alexis Gauger, PhD candidate, Department of Entomology, University of Kentucky -Field research experience, mentoring of undergraduate research assistants, development of outreach materials (blog posts), and presentation of results at academic and grower's meetings. Ryan Kuesel, PhD candidate, Department of Entomology, University of Kentucky -Field research experience, mentoring of undergraduate research assistants, development of data analysis skills. Helder Avendano, undergraduate researcher, Department of Entomology, University of Kentucky -Field research experience. Chelsea Avery, undergraduate researcher, Department of Entomology, University of Kentucky -Field research experience. Raine Esparza, undergraduate researcher, Department of Entomology, University of Kentucky -Field research experience. Mateo Garcia, undergraduate researcher, Department of Entomology, University of Kentucky -Field research experience. Jacob Hollar, undergraduate researcher, Department of Entomology, University of Kentucky -Field research experience. Sarah Jones, undergraduate researcher, Department of Entomology, University of Kentucky -Field research experience. Ben Morrison, undergraduate researcher, Department of Entomology, University of Kentucky -Field research experience. Abby Tikhtman, temporary technician, Department of Entomology, University of Kentucky -Field research experience. Sharon Badilla-Arias, PhD candidate, Dept. of Plant Pathology, Entomology, and Microbiology, Iowa State University - Field research experience, mentoring of undergraduate research assistants, development of outreach materials (blog posts) and presentation of results at academic and grower's meetings. Kephas Mphande, PhD candidate, Dept. of Plant Pathology, Entomology, and Microbiology, Iowa State University - Field research experience, mentoring of undergraduate research assistants, development of outreach materials (blog posts) and presentation of results at academic and grower's meetings. Jose Gonzalez-Acuna, Research Associate, Dept. of Plant Pathology, Entomology, and Microbiology, Iowa State University - Coordination of field research and outreach components; field research experience, mentoring of undergraduate research assistants, development of outreach materials (blog posts, podcasts, and videos) and presentation of results at academic and grower meetings. Nieyan Cheng, Ph.D. graduate, Dept. of Economics, Iowa State University; Developed economic analysis model and calculated economic indexes for all field experiments. Izzy Danicich, undergraduate research assistant, Iowa State University. Assisted in field projects. Kaitlin Diggins, undergraduate research assistant, Iowa State University. Assisted in field and laboratory projects. Kaylee Hyser, undergraduate research assistant, Iowa State University. Assisted in field projects. Jackson Goshen, undergraduate research assistant, Iowa State University. Assisted in field projects. Evelyn Bauer, undergraduate research assistant, Iowa State University. Assisted in field projects. Elijah Perrault, undergraduate research assistant, Iowa State University. Assisted in field projects. Kellie Damann, Research Associate, Cornell University. Directed performance of field experiments and conducted data analysis. Sean Murphy, Research Associate, Cornell University. Co-supervisor with Ms. Damann for field experiments. How have the results been disseminated to communities of interest?Please see the sections of this report entitled "Products" and "Other Products" for a description of the outreach products and activities. What do you plan to do during the next reporting period to accomplish the goals? Complete the project's grower manual (currently in the final editing stage) and disseminate it in both print versions (as a North Central IPM Center publication) and electronically (via the project website). Upload an additional year of podcast episodes to the project's podcast channel. Complete economic analysis (partial budget, cost efficiency ratio) of all replicated field experiments and publish the results in grower journals (e.g., American Vegetable Grower). Publish the results of field experiments (including economic analyses) from each state in academic journals (e.g., HortTechnology). Assure long-term post-project availability of the project's website resources via transfer of the entire website to the North Central IPM Center in mid-August 2023 (this has already been agreed upon with the NCIPMC). Continue laboratory experiments with biological control of cucurbit bacterial wilt. Begin gene deletion/complementation experiments to clarify genes responsible for the pathogenicity of CYVD using the pathogenicity assay developed in Year 3.

Impacts
What was accomplished under these goals? OBJECTIVE 1.Kentucky.A mesotunnel weed control trial on acorn squash compared teff living mulch mowed once during bloom, teff non-mowed, bare ground mowed once during bloom, and landscape fabric. Plots were 30 ft long, three rows with four reps, and ends opened during flowering. Bareground-mowed had significantly higher weed biomass than all other treatments, and landscape fabric had a higher marketable yield than all other treatments. Pest pressure and wilt incidence did not differ across treatments. A muskmelon pollination trial in mesotunnels (120-ft-long triple rows, four reps) compared: 1) full-season tunnels with bumble bees added at flowering ('full season'); 2) removal of ends of the tunnels during flowering ('open-ended); 3) permanent removal of covers when bloom began ('on-off'); and 4) non-covered control with organic insecticides. There were significantly fewer cucumber beetles in the full season and open-ends vs. the control. Open-ends had more marketable yield (lbs) than the other treatments, but the differences were not significant. A muskmelon variety trial crossed varieties (Astound, Athena, Divergent, and Hannah's Choice) with treatments (mesotunnel open-end vs. non-covered) on 20-ft-long, 3-row plots. Astound out-yielded Divergent and Hannah's Choice but not Athena. The mesotunnel treatment had a significantly higher yield than the non-covered treatment. Iowa.In a pollination trial, muskmelon in 150-ft-long, 3-row subplots had the following treatments: 1) one bumble bee hive/subplot, tunnels sealed all season (full-season); 2) open-ends (ends opened when bloom began, re-covered two weeks later), and 3) on-off-on (nets removed at start of bloom, re-installed two weeks later). Marketable yield was equivalent for full-season and on-off-on treatment but lower for open-ends. For weed management, muskmelon seedlings were transplanted into 30-ft-long, 3-row subplots. Full-season had bumble bee boxes for pollination. Treatments: 1) weed fabric; 2) teff seeded at 4 lb/acre, mowed three weeks after sowing; 3) teff, not mowed; 4) bare ground mowed three weeks after transplanting; and 5) bare ground, not mowed. Marketable yield was statistically the same for weed fabric and mowed teff but significantly higher than the other treatments. Weed fabric had the lowest weed biomass. In a pollination trial on acorn squash, seedlings were transplanted into 3-row, 150-ft-long rows for three treatments: 1) full-season mesotunnels with one bumblebee hive in the center row of each subplot (Full season); 2) nets removed at bloom for two weeks to allow natural pollination, then resealed (On-off-on); 3) both ends opened for two weeks at bloom, then resealed (Open ends). Visual observations of bees and squash bugs were made twice a week for two weeks during bloom. There were no significant differences in marketable yield among the treatments (Table 1). For weed management on acorn squash, seedlings were transplanted into 30-ft-long triple rows. Treatments: 1) landscape fabric; 2) teff seeded at 4 lb/acre, mowed at bloom; 3) teff at 4 lb/acre, non-mowed; 4) bare ground, mowed, and 5) bare ground, non-mowed. Covers on all treatments were removed for two weeks at bloom, then replaced. Marketable yield was highest for landscape fabric, did not differ significantly from either mowed treatment and was lowest for non-mowed bare ground and teff. New York.In a pollination trial, muskmelon plots (150' long x 3 rows wide) were compared on/off/on, open ends, and full-season treatments. Treatment had no significant effect on powdery mildew, downy mildew, or Alternaria leaf spot incidence. Bacterial wilt incidence and epidemic progress was significantly reduced in on/off/on and full season compared to open ends. Cucumber beetle populations were significantly lower in on/off/on than the other treatments. In week 4, bumblebee numbers were significantly higher in full-season than open ends. Marketable weight was also significantly higher in on/off/on than the other treatments. On/off/on for muskmelon resulted in significantly less bacterial wilt, higher populations of pollinators, and significantly higher marketable yield. In a weed control trial, treatments were: non-covered plots with landscape fabric; mesotunnel plots with landscape fabric; mesotunnel + ryegrass; and mesotunnel + ryegrass/white clover. Incidence of CYVD and pest insects was significantly suppressed in mesotunnels compared to uncovered plots. In both crops, landscape fabric significantly suppressed weeds compared to rye/clover or rye-only cover crops. OBJECTIVE 2. At ISU, we conducted pathogenicity trials for biocontrol of bacterial wilt on muskmelon seedlings, using bacterial agents previously reported to have biocontrol activity against other pathogens. Two-week-old seedlings were wound-inoculated with the pathogen in each of the following two experimental protocols: co-inoculation with a mixture of the pathogen and an equal concentration of a candidate biocontrol bacterium; and prior (3 days earlier) spray inoculation with a biocontrol candidate. Progress of bacterial wilt was monitored daily by counting the number of wilted and non-wilted leaves per seedling. In the co-inoculation trials, 11 of 20 species of biocontrol bacteria significantly suppressed wilting, whereas, in the prior-spray-inoculation trials, 5 of 12 bacteria showed significant wilt suppression. These results suggest that cucurbit bacterial wilt may be amenable to management by biological control. In addition, we developed the first pathogenicity trials for CYVD, using summer squash (cv. Zephyr) seedlings. We compared two wound-inoculation methods - using a florist frog and using a syringe - to introduce the CYVD pathogen, Serratia marcescens. For each method, inoculation was performed either once (at the expanded-cotyledon stage) or twice (the second inoculation done seven days later), using ten plants per treatment. The most consistently successful inoculation method was to inject seedlings at the cotyledon stage. Symptoms within two weeks included phloem browning and stem elongation, as well as lower dry biomass than the non-inoculated control plants. This assay represents an important breakthrough in the study of CYVD because it opens the way for further experiments to test biological control candidates and investigate host-pathogen interactions at the genetic level. OBJECTIVE 3. With guidance from the project's economists, analysis of the costs and profitability of all management options that were tested in replicated field trials in all three states is ongoing. OBJECTIVE 4. The numerous outreach activities of the project are described under Products and Other Products.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Mphande, K., Gonzalez-Acuna, J., and Gleason, M.L. 2022. Weed control on muskmelon in organic mesotunnel systems. Poster presented at annual meeting of American Phytopathological Society, Pittsburgh, PA, August 2022.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Mphande, K. Gleason, M.L., and Beattie, G.A. 2022. Developing a pathogenicity assay for Serratia marcescens on squash (Cucurbita pepo). Poster presented at annual meeting of American Phytopathological Society, Pittsburgh, PA, August 2022.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Gonthier, D. 2022. Limiting pests using exclusion netting in fruits and vegetables. University of Kentucky IPM Training School (March 9, 2022). Virtual Presentation. 20 attendees.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Fiske, K., Bessin, R., Williams, M., Gonthier, D. 2022. Row covers provide sustainable resiliency to cucurbit pests. IPM Coordinators Meeting, Denver, CO. (February 28, 2022). Poster. Presented by Ric Bessin.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Fiske, K. 2022. Row cover systems for cucurbits: Insights from research and growers perspectives. Kentucky Fruit and Vegetable Conference (January 4, 2022). Virtual presentation. 23 attendees in person.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Fiske, K., Gonthier, D., Bessin, R., Williams, M. 2022. Row cover systems for cucurbits: Insights from research and growers perspectives. Southeast Regional Fruit and Vegetable Conference (January 7, 2022). Virtual presentation. 35-40 attendees in person.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Fiske, K., Bessin, R., Williams, M., Gonthier, D. 2022. Use of row covers increases marketable yield and profit and decreases cucumber beetles and powdery mildew. University of Kentucky Department Retreat (August 12, 2022). Poster. ~50 attendees in person.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Gauger, A., Fiske, K., Gonthier, D. 2022. Foraging environment affects reproductive success in commercial Bombus impatiens colonies. University of Kentucky Department Retreat (August 12, 2022). Poster. ~50 attendees in person.
  • Type: Other Status: Published Year Published: 2022 Citation: Dammann, K., and Pethybridge, S. 2022.Reflecting on the 2022 Mesotunnel Research Trials in NY. https://www.cucurbit.plantpath.iastate.edu/post/reflecting-2022-mesotunnel-research-trials-ny. Blog post, Current Cucurbit website, December 13, 2022
  • Type: Websites Status: Published Year Published: 2022 Citation: The Current Cucurbit (project website). https://www.cucurbit.plantpath.iastate.edu/. 1,748 visits in 2022.
  • Type: Other Status: Published Year Published: 2022 Citation: Gauger, A. 2022. Who pollinates cucurbits? https://www.cucurbit.plantpath.iastate.edu/post/who-pollinates-cucurbits. Blog post, The Current Cucurbit, August 30, 2022.
  • Type: Other Status: Published Year Published: 2022 Citation: Gauger, A. 2022. How do I identify cucumber beetles? https://www.cucurbit.plantpath.iastate.edu/post/how-do-i-identify-cucumber-beetles Blog post, The Current Cucurbit, August 30, 2022
  • Type: Other Status: Published Year Published: 2022 Citation: Gauger, A. 2022. What do squash bugs look like? https://www.cucurbit.plantpath.iastate.edu/post/what-do-squash-bugs-look Blog post, The Current Cucurbit, August 30, 2022.
  • Type: Other Status: Published Year Published: 2022 Citation: Damann, K., and Pathybridge, S. 2022. Reflecting on the 2021 trials in New York. https://www.cucurbit.plantpath.iastate.edu/post/reflecting-2021-mesotunnel-trials-ny. Blog post, The Current Cucurbit, March 8, 2022
  • Type: Other Status: Published Year Published: 2022 Citation: Bessin, R., and Gonthier, D. 2022. Details matter: using row covers for pest management in cucurbits. https://www.cucurbit.plantpath.iastate.edu/post/details-matter-using-row-covers-pest-management-cucurbits. Blog post, The Current Cucurbit, February 9, 2022
  • Type: Other Status: Published Year Published: 2022 Citation: Anaonymous. 2022. NY mesotunnels: what are they good for?. https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. Bacteriophages: potential biocontrol of bacterial wilt of cucurbits. https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. Who pollinates cucurbits?. https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. What do squash bugs look like? https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. Identifying cucumber beetles. https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. What is cucurbit downy mildew? https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. What is cucurbit powdery mildew? https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. What is cucurbit yellow vine disease? https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Other Status: Published Year Published: 2022 Citation: Anonymous. 2022. Bacterial wilt of cucurbits. https://www.cucurbit.plantpath.iastate.edu/infographics. Infographic, The Current Cucurbit website.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Badilla-Arias, S., Gonzalez-Acuna, J., and Gleason, M. 2022. Optimizing pollination of organic acorn squash in mesotunnels in Iowa. Poster presented at annual meeting of American Phytopathological Society, Pittsburgh, PA, August 2022.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Badilla-Arias, S., Gleason, M.L., and Beattie, G.A. 2022. Screening for biocontrol agents of cucurbit bacterial wilt in muskmelon. Poster presented at annual meeting of American Phytopathological Society, Pittsburgh, PA, August 2022.


Progress 09/01/20 to 08/31/21

Outputs
Target Audience:Commercial vegetable growers in the U.S. Changes/Problems:Limitations due to COVID-19 were far less evident than in Year 1, but still present. Field trials in all 3 states proceeded as described in the proposal (Objective 1), and biological control research (Objective 2) began when it was possible to access ISU laboratory space in January 2021. Annual face-to-face meetings of the project team have not been possible, but we have held monthly Zoom team meetings throughout Years 1 and 2, as well as two Advisory Panel Zoom meetings in Year 1 and three in Year 2. We have also been able to resume grower field days and in-person conference presentations to a limited extent. Field experiments. One change planned for Year 3 in Iowa is to time mowing of teff based on the height of the grass (15-18 inches) rather than crop phenological stage (start of the flowering period) in order to optimize the tradeoff between weed suppresison and crop yield. Results of Year 3 trials may help to clarify which approaches are best for using mesotunnels in each region and crop. What opportunities for training and professional development has the project provided? Jose Gonzalez, Research Associate, Department of Plant Pathology and Microbiology, Iowa State University. Responsible for all aspects of project coordination and oversight of project outreach activities. Sharon Badilla, PhD candidate, Department of Plant Pathiology and Microbiology, Iowa State University - Responsible for planning and carrying out Iowa field experiments on acorn squash, and laboratory experiments on biological control of bacterial wilt of cucurbits. Participated in monthly project team meetings and Advisory Panel meetings. Kephas Mphande, PhD candidate, Department of Plant Pathology and Microbiology, Iowa State University. Planned and carried out field experiments on muskmelon, developed of a laboratory-based pathogenicity assay for cucurbit yellow vine disease (CYVD) on squash seedlings, and mentored undergraduate assistahnts. Nieyan Cheng, PhD candidate, Department of Economics, Iowa State University. Planned and conducted economic analysis of project results, and designed and executed project surveys of stakeholders. Kathleen Fiske, PhD candidate, Department of Entomology, University of Kentucky - oversaw and coordinated field experiments at University of Kentucky, mentored undergraduate assistants, and participated in monthly project team meetings and Advisory Panel meetings. Kellie Damann, Research Associae, Cornell University. Oversaw and coordinated New York field experiments and on-farm trials, mentored undergraduate assistants, and participated in monthly project team meetings and Advisory Panel meetings. Sean Murphy, Research Associate, Cornell University - Carried out New York field trials, mentored undergraduate assistants, and participated in project team meetings Alexis Gauger, undergraduate student. Field research assistant, summer 2021, University of Kentucky Chelsea Avery, undergraduate student. Field research assistant, summer 2021, University of Kentucky Kaitlin Diggins, undergraduate student. Field and lab research assistant, 2021. Iowa State University. Participated in monthly project team meetings and Advisory Panel meetings, assisted with analysis of 2020 stakeholder and project team surveys, and conducted end-of-season telephone interviews with all nine on-farm trial cooperators in 2021. Benjamin Diener, undergraduate student. Field and lab research assistant, 2021. Iowa State University. How have the results been disseminated to communities of interest?Please see the "Products" and "Other Products" sections of this report for details of our extensive and multi-featured outreach efforts in Year 2. What do you plan to do during the next reporting period to accomplish the goals?All four Objectives will proceed as described in the proposal, subject to COVID-19 restrictions and the changes described in the next section.

Impacts
What was accomplished under these goals? OUTCOMES and FINDINGS this project period. Organic food crops are the fastest-growing category in U.S. agriculture. But organic growers struggle to manage devastating diseases and insect pests with few effective tools. Our project is fine-tuning a new system called mesotunnels to help growers of organic cucurbit crops (squash, melon, cucumber) solve these problems. Mesotunnels, which are nylon-mech barriers that keep pests and diseases off crops, can ensure consistent yields. Our field trials (Objective 1) are optimizing pollination and pest, disease, and weed control in mesotunnel systems. We are also testing promising microbes for their ability to control bacterial diseases of cucurbit crops (Objective 2). We are using economic and sociological analysis to find out where and when mesotunnels and biocontrol make sense for organic growers to use (Objective 3), and our outreach intiiatives ((Objective 4) are sharing our progress with growers nationwide. Our research has found that marketable yield in organic mesotunnel systems has been strongly influenced by the crop (muskmelon vs. acorn squash) and the geographic region where the trials are held. In Iowa, for example, pollination trials for muskmelon have consistently shown that the full-season mesotunnel approach has higher yield than on-off-on or open-ends mesotunnel treatments, whereas the full-season treatment has had the lowest marketable yield for acorn squash. In weed control trials, living-mulch species and seeding rates have differed among states based on regional recommendations. We have also found that a single mowing of living mulches during bloom of the cucurbit crop can increase marketable yield in some cases (for example, muskmelon in Iowa) but not for acorn squash in Iowa, and not consistently for either crop in other regions. OBJECTIVE 1. POLLINATION AND WEED CONTROL TRIALS This project year. Replicated experiments with muskmelon and acorn squash took place during 2021 (Year 2 of the project) in Iowa, Kentucky, and New York. Iowa. Pollination trials on both crops used 150-ft-long, 3-row mesotunnels. Treatments: tunnels closed all season, with a purchased hive of bumble bees to provide pollination ("full season"); tunnels opened for 2 weeks during flowering, then re-closed ("on-off'-on"); and tunnel ends opened for 2 weeks during flowering, then re-closed ("open ends"). For muskmelon (cv. Athena), marketable yield was highest for full-season than the other treatments. For acorn squash (cv. Table Ace), the on-off-on and open-ends treatments had much higher marketable yield than full-season. Weed management trials were done on 30-foot-long, triple-row mesotunnels; muskmelon trial used the "full season" strategy and acorn squash used "on-off-on." Treatments (applied to the soil alleys between crop rows): landscape fabric; teff, mowed when nets were removed; teff with no mowing; bare ground, mowed when nets were removed; and bare ground without mowing. Marketable yield for muskmelon (cv. Athena) was highest for landscape fabric and mowed teff, and 25-30% lower for the other treatments. Mowing teff and bare-ground plots halved the end-of-season weed biomass. For acorn squash (cv. Table Ace), landscape fabric out-yielded than other treatments, and mowing reduced end-of-season weed biomass. For muskmelon, mowing teff at mid-season minimized yield drag, but not for acorn squash. Kentucky. Pollination. An acorn squash (cv. Table Ace) trial in mesotunnels (120-ft-long triple rows, 4 replications) compared 4 treatments: full-season tunnels with purchased bumble bees ("full season"); covers removed for 2 weeks during bloom ("on-off-on"); ends uncovered for 2 weeks during bloom ("open ends"); and permanent removal of covers when bloom began ("on-off"). The full season treatment had fewer pollinators than other treatments, suggesting the purchased bumble bee colonies were less efficient pollinators compared to wild bees. There was no difference in marketable yield among treatments. Weed management. Another acorn squash trial, in triple-row, 30-ft-long plots with open-ends mesotunnels, compared 4 treatments: landscape fabric, teff non-mowed, teff mowed once during squash bloom, and buckwheat mowed once during squash bloom. There were no differences among treatments in either weeed biomass or marketable yield. Foliar disease management. An acorn squash trial assessed impact of mesotunnels and fungicide spraying on powdery mildew. Experimental design was a 2x2 factorial (open-ends mesotunnels vs no tunnels, and sprayed vs. unsprayed) in 30-ft-long, triple-row subplots with 4 replications. Mesotunnels significantly reduced the percentage of leaf area with powdery mildew, but organic fungicide treatments had no significant effect. New York. Weed, disease, and insect pest control. A field trial evaluated mesotunnels and weed suppression options for muskmelon (cv. Athena) and acorn squash (cv. Table Ace). Treatments: (i) non-covered plots with landscape fabric for weed suppression; and full-season mesotunnels with (ii) landscape fabric (iii) ryegrass; and (iv) ryegrass/white clover. Powdery mildew incidence was significantly higher in muskmelon than acorn squash, but severity was higher in acorn squash. Bacterial wilt (BW) and cucurbit yellow vine disease (CYVD) appeared only in muskmelon and acorn squash, respectively. Cucumber beetles and squash bugs were significantly higher in uncovered plots than mesotunnels. The mesotunnels significantly reduced incidence of cucumber beetles and squash bugs as well as BW and CYVD. In muskmelon, marketable fruit weight was significantly lower in mesotunnels and not significantly affected by cover crop. In acorn squash, the non-covered plot had significantly more unmarketable fruit than in mesotunnels. Unmarketable acorn squash was mainly attributed to being soft and misshapen; incidence of soft fruit was significantly higher in uncovered plots compared to the mesotunnels. In sum, mesotunnels resulted in lower marketable yield for muskmelon and but did not impact marketable yield in acorn squash. OBJECTIVE 2. BIOLOGICAL CONTROL TRIALS Bacterial wilt. Lab trials at Iowa State University (ISU) evaluated more than 20 strains of bacteria previously shown to be effective in suppressing plant-pathogenic bacteria. Biological control strains and the bacterial wilt pathogen, Erwinia tracheiphila (Et), were cultured, mixed together, and inoculated into 2-week-old muskmelon (cv. Athena) seedlings. Wilting was monitored every 2 days for 3 weeks. Several biological control candidates suppressed bacterial wilt symptoms significantly in repeated trials. In addition, several strains of phage (bacterial virus) were isolated from striped cucumber beetles from IA and KY cucurbit fields. These phages were purified and their concentrations are being amplified. Cucurbit yellow vine disease (CYVD). A new inoculation method resulted in clear-cut symptoms (browning of the vascular system and roots) within 3 weeks after injection of stems with the CYVD bacterium (Serratia marcescens). This opens the door to determining which bacterial genes and enzymes are responsible for causing CYVD - and to developing ways to neutralize them and protect cucurbit crops. OBJECTIVE 3. SOCIOECONOMIC ANALYSIS The project team created a final version of a Year 3 grower survey to be sent to vegetable growers throughout IA, NY, KY, and neighboring states in January 2021 to gauge project impact. The economics team also finalized a template for analysis of economic data for all years of the project, based on results of field experiments. OBJECTIVE 4. OUTREACH The project's extensive face-to-face and online outreach (blogs, videos, podcasts) are posted on the project website and spread by social media (Facebook and Twitter). See "Products" and "Other Products" sections of this report for details.

Publications

  • Type: Websites Status: Published Year Published: 2020 Citation: The Current Cucurbit (project website). https://www.cucurbit.plantpath.iastate.edu/ Total visits, January-October 2021: 895 (188 from mobile devices, 707 from desktop computers). Twitter impressions, January-October 2021: 1,031.
  • Type: Other Status: Published Year Published: 2021 Citation: Damann, K., and Pethybridge, S. 2021. The Current Cucurbit podcast series. Veg Edge newsletter, Vol. 17, Cornell University Cooperative Extension. October 4, 2021. p. 11.
  • Type: Other Status: Published Year Published: 2021 Citation: Damann, K., and Pethybridge, S. 2021. Mesotunnels: Next Best Tool for Organic Cucurbit Growers in the Northeastern US. Produce Pages, Cornell University Cooperative Extension, April 2021. p. 6.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Fiske, K. 2021. Optimizing row cover systems for cucurbits in Kentucky, Kentucky Fruit and Vegetable Conference, Lexington, KY, January 12, 2021. 158 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Gonthier, D. 2021. Multi-functional agriculture: Balancing trade-offs to improve sustainability. Seminar, Department of Entomology, University of Kentucky, April 1, 2021. 30 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Gonthier D. 2021. Multifunctional agriculture: Balancing trade-offs to improve sustainability. University of Kentucky. Department of Plant and Soil Science. Department Seminar. March 23, 2021. 35 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Gonthier D. 2021. Multi-functional agriculture: Balancing pest/disease control with pollination: A case study of using row covers in squash. Classroom case study presentation. Agroecology SAG/PLS390 February 26, 2021. 21 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Gleason, M. 2021. Do mesotunnels make sense for organic cucurbit production? Seminar, Department of Plant Pathology, University of Wisconsin-Madison, December 7, 2021. 26 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Diggins, K., and Morton, L.W. 2021. o What are growers saying about mesotunnel systems for organic cucurbits? https://www.cucurbit.plantpath.iastate.edu/post/what-are-growers-saying-about-mesotunnel-systems-organic-cucurbits
  • Type: Other Status: Published Year Published: 2021 Citation: Damann, K., and Pethybridge, S. 2021. Reflecting on the 2020 Preliminary Results of the Mesotunnel System in NY https://www.cucurbit.plantpath.iastate.edu/post/reflecting-2020-preliminary-results-mesotunnel-system-ny
  • Type: Other Status: Published Year Published: 2021 Citation: Badilla, S. 2021. On-site presentation of OREI acorn squash field trials, Iowa State University Field Day, ISU Horticulture Research Farm, Ames, Iowa, July 22, 2021. 225 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Mphande, K. 2021. On-site presentation of OREI muskmelon field trials, Iowa State University Field Day, ISU Horticulture Research Farm, Ames, Iowa, July 22, 2021. 225 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Nair, A. 2021. Presentation during field day at OREI on-farm trial site, Scattergood Farm, West Branch, Iowa, September 15, 2021. 125 participants.
  • Type: Other Status: Published Year Published: 2021 Citation: Badilla, S. 2021. Dos and don'ts when using mesotunnels in commercial organic acorn squash production https://www.cucurbit.plantpath.iastate.edu/post/dos-and-donts-when-using-mesotunnels-commercial-organic-acorn-squash-production
  • Type: Other Status: Published Year Published: 2021 Citation: Fiske, K. 2021. Reflecting on University of Kentuckys 2020 mesotunnel experiments https://www.cucurbit.plantpath.iastate.edu/post/reflecting-university-kentuckys-2020-mesotunnel-experiments
  • Type: Other Status: Published Year Published: 2021 Citation: Cheng, N., and Zhang, W. 2021. What do Farmers and Researchers Think About Mesotunnels and Biological Controls for Cucurbit Crops? Responses from 2020 surveys https://www.cucurbit.plantpath.iastate.edu/post/what-do-farmers-and-researchers-think-about-mesotunnels-and-biological-controls-cucurbit-crops
  • Type: Other Status: Published Year Published: 2021 Citation: Avery, C. 2021. Efficacy of pest control and pollination management in organic cucurbit production with row covers. November 30, 2021. Agricultural and Medical Biotechnology 395/399 Undergraduate Student Symposium, University of Kentucky, Lexington, KY. 20 attendees.
  • Type: Other Status: Published Year Published: 2021 Citation: Fiske, K. 2021. Optimizing row covers in cucurbit production. Symposium: Expanding the Pest Management Tool-kit: Adapting Pest Management Alternatives for Diverse Farming Communities. June 23, 2021. North Central Branch, Entomology Society of America. Virtual presentation. 28 attendees.


Progress 09/01/19 to 08/31/20

Outputs
Target Audience:Commercial growers of cucurbit vegetable crops in the eastern half of the U.S. Changes/Problems:A project-wide obstacle in Year 1 was the coronavirus pandemic. The pandemic constricted field trials (Objective 1) at Cornell University due to a state-mandated lockdown, delayed plans to start the biological control experiments (Objective 2) at Iowa State University by 8 months, prevented in-person interviews to be conducted for the socioeconomic portion of the research (Objective 3), and sharply limited in-person collaboration of project personnel with cooperators in on-farm demonstration trials (Objective 4). The outlook for overcoming these Year 1 imitations in Year 2 is uncertain, but the project team will adjust to whatever the pandemic throws at us. Despite the pandemic, our project advanced significantly in Year 1. Objective 1 field experiments in Iowa and Kentucky, and a nonreplicated trial in New York, advanced knowledge about mesotunnels in several ways: Pollination in mesotunnels played out differently for muskmelon than acorn squash. The fact that acorn squash foliage filled the full-season-mesotunnels much more than muskmelon may have made it more difficult for bumble bees to find acorn squash flowers, which in turn may have limited pollination and yield. In muskmelon, on the other hand, full-season mesotunnel treatments often out-yielded other treatments, suggesting that bees found flowers more readily on that crop. Interestingly, mesotunnels in which only the ends were opened yielded only slightly less than the full-season tunnels (muskmelon) and, in acorn squash, sometimes exceeded the yield from full-season tunnels. On-off-on treatments - which removed the cover fabric entirely for 2 weeks during bloom - had the most pollinator visits but often the lowest yields, apparently because pest and disease pressure was greatest in these treatments. These findings offer encouraging evidence that an open-ends strategy could provide a "sweet spot" for organic mesotunnel systems by allowing enough natural-pollinator access to assure acceptable yield while limiting crop access by pest insects and the bacteria they vector. We therefore plan to continue trialing open-ends treatments on both cucurbit crops. Weed management. Seeding teff as a living mulch was highly effective in suppressing weed growth between crop rows. Interestingly, teff depressed crop yield in both crops in Iowa, but not in Kentucky. The yield depression in Iowa coincided with a dry summer; vigorous root growth by teff, which is drought-adapted, may have diverted water and nutrients from the cucurbit crops, and shading by teff may have also contributed to yield loss. For Year 2, therefore, Objective 1 trials will include mid-season mowing of teff mulch in an effort to preserve its weed-suppressive benefit while minimizing its competition with the cucurbit crops. Unexpectedly, foliar diseases - powdery mildew, downy mildew, and Alternaria leaf spot - were less severe under mesotunnels compared to exposed treatments. A possible reason for this is shorter dew periods under the mesotunnels, which could curtail high-humidity periods that can promote these diseases. In Year 2, therefore, we plan to compare relative humidity and the duration of wet periods inside vs. outside mesotunnels to see if mesotunnels modify the crop microenvironment to mitigate disease development. Objectives 2, 3, and 4 will proceed as described in the proposal, to the extent possible with coronavirus restrictions. What opportunities for training and professional development has the project provided?Research Associate training and professional development: Jose Gonzalez, Iowa State University, Research Associate - Research project coordination, creation of electronic outreach products (websites, blog posts, videos), promotion of project via social media, mentoring of graduate students and undergraduate research assistants Kellie Damann, Cornell University, Research Associate - Field research coordination and conduct; development of outreach products (blog posts), mentoring of undergraduate research assistants Sean Murphy, Cornell University, Research Associate - Field researchcoordination and conduct; development of outreach products (blog posts), mentoring of undergraduate research assistants Delia Scott-Hicks, University of Kentucky - Field research coordination and conduct Graduate student training and professional development: Kephas Mphande, PhD candidate, Department of Plant Pathology & Microbiology, Iowa State University - Field and lab research experience; development of outreach products (blog posts, instructional videos), Sharon Badilla, M.S. candidate, Department of Plant Pathology & Microbiology, Iowa State University - Field and lab research experience; development of outreach products (blog posts),mentoring of undergraduate research assistants Nieyan Cheng, PhD candidate, Department of Economics, Iowa State University - Research experience in economic analysis and grower surveys; development of outreach products (blog posts) Katie Fiske, M.S. candidate, Department of Entomology, University of Kentucky - Field research experience, mentoring of undergraduate research assistants Robby Brockman, M.S. candidate, Department of Entomology, University of Kentucky - Field research experience, mentoring of undergraduate research assistants How have the results been disseminated to communities of interest?Despite pandemic-imposed limitations, the team has developed and posted to the project's website, The Current Cucurbit (https://www.cucurbit.plantpath.iastate.edu), many virtual outreach products, as well as delivered many person and Zoom-facilitated grower education sessions. For details, please see the "Products" and "Other Products" sections of this report. What do you plan to do during the next reporting period to accomplish the goals?Objectives 2, 3, and 4 will proceed as described in the proposal, to the extent possible with coronavirus restrictions.

Impacts
What was accomplished under these goals? Impact of the project: Organic food crops are the fastest growing category in U.S. agricuture. But organic vegetable growers also strugggle to manage devastating diseases and pest insects with few effective tools. Our project is fine-tuning a new system called mesotunnels to help growers of organic cucurbits (squash, melon, cucumber) solve these problems. Mesotunnels - nylon-mesh barriers that keep pests and diseases off crops - can ensure consistent yields. Our mesotunnel field trials (Objective 1) aim to optimize pollination and pest, disease and weed control in this new management system. We are also testing promising microbial candidates for their ability to control bacterial diseases of cucurbits (Objective 2), alone and in combination with mesotunnels. We will use economic and sociological analysis to find out where and when mesotunnels and biological control are adaptable by organic cucurbit growers, and our outreach (Objective 4) will share the advances with growers nationwide. This project year...In Objective 1, replicated field experiments with muskmelon and acorn squash took place on university farms in Iowa and Kentucky, and a demonstration trial was conducted at Cornell University. Iowa. Results of pollination trials - on triple-row, 150-foot-long mesotunnels - differed between the two crops. Treatments were: tunnels closed all season, with a purchased hive of bumble bees placed underneath to provide pollination ("full season"); tunnels opened completely for 2 weeks during flowering of the crop, then re-closed ("on-off-on"); and tunnel ends opened for 2 weeks during flowering ("open ends") The on-off-on and open-ends treatments depended on natural polinators rather than purchased bees. For muskmelon, marketable yield was highest for the full-season treatment, intermediate for the open-end treatment, and lowest for the on-off-on treatment. For acorn squash, in contrast, marketable yield was highest yield in the on-off-on treatment, lowest in the full-season treatment, and intermediate in the open-ends treatment. Weed management trials - in full season mesotunnels on replicated, 30-ft-long, triple-row plots - compared 4 treatments: 1) polyethylene landscape fabric; 2) teff (a cereal crop used as a mulch) seeded at 4 lb/acre; 3) teff at 8 lb/acre; and 4) bare ground (control). In muskmelon plots, marketable yield for landscape fabric was about twice as high as the other three treatments, although teff suppressed weeds almost as well as landscape fabric. Acorn squash marketable yield showed less advantage for landscape fabric over teff, and teff treatments out-yielded the bare-ground control. The yield penalty from teff in both crops could be caused by competition with the crop for nutrients, water, and sunlight. Kentucky. Pollination. An acorn squash trial in mesotunnels (120-ft-long triple rows, 4 replications) compared 4 treatments: full-season tunnels with purchased bumble bees added ("full season"); complete removal of covers for 2 weeks during bloom ("on-off-on"); removal of the ends of the covers for 2 weeks during bloom ("open ends"); and permanent removal of covers when bloom began ("on-off"). Marketable yield was significantly higher in the open-ends treatment than the other treatments, and bee abundance was significantly lower in the full-season treatments than the other treatments. A parallel experiment on muskmelon differed in that subplot length was 30 ft rather than 120 ft.; in that trial, the full season treatment had significantly higher marketble yield than the on-off or on-off-on treatments and the open-ends treatment was intermediate. Weed management. Another acorn squash trial, in replicated, triple-row, 30-ft-long plots with on-off-on mesotunnels, compared 4 living much treatments for the soil strips between black-plastic crop rows: buckwheat (seeded at 90 lb/A) and three seeding rates of teff: 12, 24, or 36 lb/A. Marketable yield did not differ significantly among the treatments, but weed suppression was more effective for buckwheat and the two higher rates of teff than for the lowest rate of teff. Foliar disease management. An acorn squash trial assessed impact of mesotunnels and fungicide spraying on powdery mildew, the most important fungal disease of cucurbits. Experimental design was a 2x2 factorial (on-off-on mesotunnels vs no tunnels, and sprayed vs. unsprayed) in 30-ft-long, triple-row subplots with 4 replications. Both mesotunnels and fungicide spraying significantly suppressed powdery mildew, and combining both practices gave the most suppression. The mesotunnel treatments also had significantly higher marketable yield than the no-tunnel treatments. New York. A nonreplicated demonstration trial - the only type of trial allowed in NY in 2020 due to New York's pandemic lockdown rules - was a 2x2 combination of crop ('Honey Bear' acorn squash and 'Athena' muskmelon) and crop covering (full-season mesotunnels with purchased bumble bees inserted, and a non-covered control). Triple-row, 50-ft-long plots had landscape-fabric mulch between rows. Acorn squash. Marketable yield was similar for the 2 treatments. Striped cucumber beetle and squash bug populations were much higher on non-covered plants, whereas aphid populations built up under mesotunnels by the end of the season. Downy mildew, powdery mildew, and CYVD severity, although low, was much higher in the non-covered than the mesotunnel plot. Muskmelon. Number of marketable fruit in the mesotunnel plot was nearly 3x higher than for the control plot. Severity of bacterial wiltwas much lower in the mesotunnel than the control; while powderyand downy mildew incidence was higher in the covered plot but very low in general (less than 2%). Objective 2 (biological control of cucurbit bacterial diseases). Year 1 experiments at Iowa State were delayed by lockdowns of laboratory facilities that persisted through most of 2020. However, we obtained numerous species of biological-control-candidate bacteria from our own and other labs, and have obtained many strains of the target pathogens - Erwinia tracheiphila and Serratia marcescens - in preparation for starting in vitro and in vivo screening for suppression of the pathogens in January 2021. Objective 3. Socio-economic research included development of written surveys for stakeholders, as well as conducting telephone interviews with cucurbit growers in Iowa, Kentucky, and New York, in order to gauge their viewpoints on the project and its new strategies. Data analysis and interviews are ongoing. The team also finalized criteria to be measured in economic analyses of project data. Objective 4. Although face-to-face outreach was prohibited from March 2020 to the present due to the pandemic, numerous presentations at grower conferences and other gatherings carried the project's messages to stakeholders. A project website, The Current Cucurbit (https://www.cucurbit.plantpath.iastate.edu) includes numerous blog posts as well as the first in a series of videos (see "Products" and "Other Products" sections of this report). The project's Advisory Panel has met twice (July and October 2020) by Zoom with project PIs and graduate students. On-farm trials took place in all 3 states(3 in Iowa, 3 in New York, and 2 in Kentucky) where different mesotunnel settings were tested and different cucurbit crops were covered. Yield data and - in some cases - pest-disease incidence was recorded.

Publications

  • Type: Websites Status: Published Year Published: 2020 Citation: https://www.cucurbit.plantpath.iastate.edu/
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Bessin, R. 2019. IPM for small farms. IPM class, University of Kentucky, December 4, 2019. 20 students.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Bessin, R. 2020. Vegetable insect pest update. South farm, University of Kentucky, February 18, 2020. 50 attendees.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Bessin, R. 2020. Outmaneuvering insect pests. Harlan County Webinar. June 4, 2020. 23 attendees.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Bessin, R. 2020. IPM for Small Farms. County Agent Training Webinar. 46 attendees.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Nair, A. 2020. Disease and pest management strategies in key vegetable crops. Iowa Fruit and Vegetable Growers Association, January 23, 2020. 35 attendees.
  • Type: Other Status: Published Year Published: 2020 Citation: Nair, A. 2020. Small Farms Podcast. Planting, cool-season-crop row covers, and high tunnels. March 24, 2020. 150 downloads.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Nair, A. 2020. Pest Management Workshop. https://www.extension.iastate.edu/vegetablelab/iowa-vegetables-pest-management. April 9, 2020. 1,445 views.
  • Type: Other Status: Published Year Published: 2020 Citation: Nair, A. 2020. Small Farms Podcast.Raised bed vegetable production. April 14, 2020. 75 downloads.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Bessin, R. 2019. Pumpkin Insect Management. Pumpkin webinar. December 19, 2019. 44 attendees.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Bessin, R. 2020. Scaling up IPM. Kentucky Vegetable Growers Association. January 6, 2020. 61 attendees
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Bessin, R. 2020. Insect challenges from 2019. Lincoln Count, Kentucky, Produce Auction. January 16, 2020. 53 attendees.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Bessin, R. 2020. Managing key vegetable insect pests. Kentucky County Agent webinar, February 6, 2020. 53 attendees.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Bessin, R. 2020. Vegetable insect update. Growers School. Mt. Vernon, IL, February 5, 2020. 27 attendees.