Comparison of Reduced-Application and Sulfur-Based Fungicide Programs on Scab Intensity, Fruit Quality, and Cost of Disease Control on Peach.

Abstract

The costs of two reduced-fungicide programs (5 applications each) and two micronized wettable-sulfur programs (6 or 11 applications each) and their impact on scab control and fruit quality were evaluated on 'Contender' and 'Cresthaven' peach over two growing seasons. The reduced-fungicide programs consisted of applications of chlorothalonil and captan or chlorothalonil, azoxystrobin, and captan. All programs provided excellent scab control when disease pressure was low to moderate; however, six sulfur applications did not adequately control scab under high disease pressure. The product cost of the reduced-fungicide chemicals was higher, but comparable with six applications of micronized wettable sulfur or nine hypothetical applications of nonmicronized wettable sulfur per season. The reduced-fungicide programs were preferable to weekly applications of sulfur (11 applications) because they equally controlled scab at a reduced cost and have greater potential to protect against other summer diseases. The fungicide program effects on fruit quality were inconsistent. A more detailed study is needed to determine if a relationship between fungicide programs and fruit quality exists.