Alternatives to Vinclozolin (Ronilan) for Controlling Gray and White Mold on Snap Bean Pods in New York

Abstract

Human health and environmental concerns have led to the eventual phase-out of benomyl (Benlate) and vinclozolin (Ronilan), two efficaceous, broad spectrum fungicides widely used on a range of crops, including snap beans. With fewer registered fungicides available for mold control, snap bean growers are in need of alternatives. We compared six foliar fungicides against Ronilan for gray (Botrytis cinerea) and white (Sclerotinia sclerotiorum) mold control on snap bean pods in New York, using data collected over three consecutive years. Ronilan gave the best overall mold control and highest yields of healthy pods. Trifloxystrobin (Flint), iprodione (Rovral), and cyprodinil plus fludioxonil (Switch) gave gray mold control comparable to that obtained with Ronilan. Switch and Rovral significantly reduced the incidence of white mold on pods, but were not as effective as Ronilan. Thiophanate-methyl (Topsin M) was as effective as Ronilan in controlling white mold on pods. Switch was the most promising alternative to Ronilan for controlling both gray and white mold on pods and for increasing marketable yield. A combination of Rovral and Topsin M may also be an effective alternative to Ronilan. Accepted for publication 13 September 2002. Published 23 September 2002.