Advancing IPM for Celery Growers in Michigan, California and Florida
Celery is the third most important salad crop in the US and is valued at over $250 million. One acre of celery can be worth up to $10,000 in the fresh market. Collectively, California, Michigan, and Florida provide 98% of all of the celery produced in the US (FCIC 1999). In 2002, Michigan State University was awarded a USDA CSREES Risk Avoidance and Mitigation Program (RAMP) Grant to increase IPM among celery growers in Michigan, California and Florida. The generous grant from AFT helped leverage these funds, which were drastically reduced from the original budget.
Because there are fewer growers in Michigan, and more specific work on celery in Michigan, growers in this state often set the bar for testing and adopting new practices. Therefore, funding from AFT focused on the Michigan market, working with approximately 42% of the total potential customers (10 out of 24 growers), who grow approximately 43% of the state’s celery acreage (994 out of 2,200 acres).
Celery growers rely on fungicides for disease management. Mancozeb (Dithane) and benomyl (Benlate) were widely used historically for blight control, but all legal uses of mancozeb, related dithiocarbamates, and benomyl on celery have been rescinded by the EPA. As a result, these growers depend on frequent sprays of chlorothalonil (Bravo), a B2 carcinogen. While azoxystrobin (Quadris) and propiconazole (Tilt) offer alternatives, both are at risk of pest resistance developing and are more expensive than chlorothalonil, thus making adoption of these materials challenging.
Project goals and objectives
(1) Of approximately 100% of growers who are currently using chlorothalonil, the use of B2 carcinogenic fungicides (chlorothalonil) will be displaced by a reduced-risk fungicide azoxystrobin (Quadris) for two applications on 20% of the celery acreage in Michigan. This target can be achieved with approximately two growers in the state who grow substantial acreage of celery.
(2) Of the 24 Michigan growers who use a calendar-based spray schedule, one grower will use weather parameters, including the duration of leaf wetness and the temperature during the leaf wetness period, to time fungicide sprays on an experimental plot on their farm, and agree to host a field meeting at the demonstration site for all other growers in the state. The demonstration/experimental plot will be approximately one-sixth of an acre, representing a potential risk of almost $1,700.
(1) Data collected from growers at the 2006 annual meeting indicate that the project was only partially successful at achieving the first target of displacing the use of chlorothalonil by a reduced-risk fungicide (Quadris) on 20% of the celery acreage in Michigan. Among the 10 growers who completed surveys, two growers began using Quadris in 2005, which accounted for approximately 230 acres, or 10% of the overall acreage in Michigan in 2005. Because not all Michigan growers completed the survey, we do not know if there are more growers who have begun using Quadris as a result of this project.
(2)The project was successful at achieving the second target, which was one grower using a disease predictor and hosting a field meeting at his farm in 2005. When asked about the likelihood of using a disease predictor in 2006, the majority of survey respondents (60%) indicated that they were at least “somewhat likely” to use one, with 20% of them indicating that they were “very likely” to use one in 2006. These responses are very encouraging for the use of disease predictors, especially given the results of the project studies, which indicate that as many as seven fungicide applications could be saved over the course of a growing season. If all 60% of these respondents do indeed begin using a disease predictor, this will impact 670 acres, or 30% of the celery acreage in Michigan.
Web address for Dr. Mary Hausbeck