Optimizing management of diseases affecting vegetables grown on Long Island within organic as well as conventional production systems
CALS Impact Statement
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.)
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
• disease occurrence is changing,
• new pathogen strains are evolving that are able to resist (tolerate) fungicides that were highly effective or attack varieties with genetic resistance,
• new management tools (fungicides and resistant varieties) do not need to be proven effective to be commercialized, and
• 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 NY are directly affected, growers in other states share some of the same needs, and other people in NY 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.
Conventional and organic farms were visited to determine which diseases were present, 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 with 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, Phytophthora blight, and downy mildew. 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-rinded pumpkin varieties and experimentals were evaluated for resistance to blight. Clover-planted driveways were tested for blight suppression on farms. Impact on plant productivity of ambient ozone was examined by assessing damage to pumpkin crops and 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 and clover living mulch between black plastic mulch. Information from this work was provided to growers throughout the northeastern US through newsletter articles and meeting presentations.
Research conducted in 2007 generated information that is influencing management guidelines for 2008 to ensure that growers can continue to effectively control important diseases and maintain economic crop production. Resistant varieties are an important management tool. Varieties of zucchini, acorn, and summer squash with resistance to powdery mildew generally did not exhibit the level of disease suppression in 2007 as they had in 2006; many were no longer effective, suggesting the pathogen has evolved a new strain able to overcome the one major gene for resistance that all these varieties have. The single variety of each squash type tested with resistance from both parents performed better than the majority of varieties available, which have resistance from one parent. Strains of the powdery mildew fungus were detected to be able to tolerate high concentrations of the active ingredients in the main mobile fungicides currently in use. This finding may account for variable, sometimes only moderate control obtained with some products in fungicide evaluations and commercial fields. The cucurbit downy mildew pathogen population evidently had a sufficient level of resistance to two commonly used fungicides that the products tested with these fungicides were ineffective. Newer fungicides that were tested proved effective for downy mildew.
funding source description
Department of Agriculture
New York State Department of Agriculture and Markets