- Apple farmers in New York State and other eastern states must apply fungicides to their trees 10 to 15 times during the growing season to protect the crop from fungal pathogens that would otherwise destroy the crop and debilitate the trees. Apple farmers depend on university researchers for unbiased evaluations of the many different fungicide products that are labeled to protect apple trees from fungal diseases. Dr. Dave Rosenberger conducts detailed field trials with fungicides each summer and provides those results to fruit growers in New York and surrounding states. These scientific comparisons and the recommendations that are derived from them help growers to know which products will be effective for the specific diseases that are prevalent in their orchards, the rate at which the product should be applied, and the best time for making those applications. The recommendations derived from these trials are made available to fruit growers via extension newsletters and oral presentations at fruit grower meetings. Results from Dr. Rosenberger’s trials are used extensively throughout the northeast and impact spray decisions not only for New York apple growers, but also for apple growers throughout much of eastern United States.