Optimizing management of diseases affecting vegetables grown on Long Island within organic as well as conventional production systems
CALS Impact Project
Research conducted in 2008 generated information influencing management guidelines for 2009. Resistance in the cucurbit powdery mildew pathogen to FRAC Code 1 (Topsin M) and to Code 11 (Flint) fungicides were detected in all spring squash plantings where a bioassay was conducted on 17 July. Therefore, fungicides in these classes are not recommended. Pathogen strains were detected able to tolerate higher concentrations of Code 3 and 7 fungicides (Rally, Procure, and Pristine) than Code 13 (Quintec). These fungicides were all equally highly effective when tested alone, indicating that their efficacy was not affected by the pathogen developing resistance; however, control in commercial fields was not as good. Evaluations of powdery mildew resistant cucurbit varieties revealed a range in ability to suppress disease severity among varieties as well as crop types. Generally varieties with two copies of the major resistant gene, one from each parent, were more effective. Best control was achieved with butternut squash and melons resistant to both races 1 and 2 of the pathogen. Least control was achieved with pumpkin. Several biopesticides were found to be highly effective for managing foliar diseases in organically-produced tomato. Participation in the national downy mildew forecasting program lead to timely information on occurrence of this important cucurbit disease and educational materials for growers. A new pepper variety exhibited very good resistance to Phytophthora blight. Spring-planted mustard biofumigant cover crop showed good promise for managing blight as well as weeds in an observational study. An investigation of this pathogen has revealed that resistance to Code 4 fungicides (Ridomil) is present on some farms, many years after it was last used, and both mating types occur in many fields.
impact statement issue
To be profitable, vegetable growers in New York need up-to-date information on disease occurrence and management in order to enable them to successfully produce a healthy, high quality crop. While all growers need information, those producing crops organically, with reduced tillage, with compost and other organic amendments and/or under the environmentally unique growing conditions of Long Island need information applicable to their particular situation. It is challenging to remain successful when: 1) disease occurrence is changing, 2) new pathogen strains are evolving that are able to resist (tolerate) fungicides that were highly effective or attack varieties with genetic resistance, 3) new management tools (fungicides and resistant varieties) do not need to be proven effective to be commercialized, and 4) there is incomplete understanding of the biology of a pathogen (such as conditions that favor development of disease, survival time in soil, and source of inoculum). While growers in New York are directly affected, growers in other states share some of the same needs, and other people in New York are indirectly affected due to the importance of the agricultural industry, not only as a source of state income, but also the increasing consumer interest in locally produced food, on-farm agri-tainment (such as pumpkin picking), and open space. There is also a need to understand the impact of air pollution on crop production.
impact statement response
Conventional and organic farms were visited to determine diseases occurring, how well they were being managed, and farm-to-farm variation in occurrence and severity. This information was used to identify research needs and provide growers timely recommendations through a weekly newsletter. Experiments were conducted to evaluate control practices. Efficacy was examined for registered and experimental conventional fungicides, biopesticides, and products for organic production to manage cucurbit powdery mildew, cucurbit downy mildew, Phytophthora blight, and foliar diseases of tomato. Varieties resistant to powdery mildew were evaluated for disease suppression, yield, and fruit quality. Fungicide sensitivity of the powdery mildew pathogen population was examined in commercial and research fields for fungicides at-risk for resistance development. Efficacy of these products was evaluated. Hard-rind pumpkin varieties and experimentals were evaluated for resistance to blight. Occurrence of the pathotypes of the cucurbit downy mildew pathogen was monitored as part of a national forecasting program. A preliminary observational study was conducted to assess the potential utility of mustard biofumigant cover crop for managing Phytophthora blight. Impact on plant productivity of ambient ozone was examined by conducting research with snap bean and clover bioassay systems developed to assess impact for a national research project. Research was done with a reduced tillage pumpkin production system. Information from this work was provided to growers throughout the northeastern U.S. through newsletter articles and meeting presentations.
impact statement summary
The goal of this project is to enable vegetable growers in New York to be profitable by effectively controlling diseases in both conventional and organic crops. Information obtained on disease occurrence, severity, and variation among farms is used to guide both extension and research activities. Research on new management practices provides growers with the information needed to select an effective management program. This work is being done on Long Island in the most important agricultural county in New York (based on overall value of production.)
