Development and Evaluation of an Integrated, Reduced-Spray Program Using Sterol Demethylation Inhibitor Fungicides for Control of Primary Apple Scab

Abstract

An integrated, reduced-spray program for control of primary apple scab infections was developed and evaluated for three consecutive years in nine commercial apple orchards and for 2 of the same 3 yr in five additional orchards in western New York. Growers were advised to make four applications of a sterol demethylation inhibitor fungicide (i.e., fenarimol, flusilazol, or myclobutanil), whose timings were to be independent of the occurrence of apple scab infection periods but were to coincide with applications of insecticides or acaricides at or near the following four phenological stages: 1) tight cluster, 2) pink bud; 3) petal fall; and 4) approximately 10 days after petal fall(.)