Evaluation of fungicide timing strategies for control of mummy berry disease of rabbiteye blueberry in Georgia

Abstract

Mummy berry disease, caused by the fungus Monilinia vaccinii-corymbosi, is a persistent problem on rabbiteye blueberries in southern Georgia. Detailed information about the epidemiology of the disease in this production system is lacking, hence management strategies have relied on repeated applications of fungicide over a relatively long period of host development (from bud swell throughout bloom). This study evaluated various host phenology-based fungicide application schedules in 1999 and 2000 to generate baseline knowledge for optimizing disease control with reduced fungicide inputs. The schedules differed in the number of pre-bloom and bloom sprays and in the type of fungicide used. Results indicated that pre-bloom sprays contributed relatively little to reductions in the incidence of fruit infection. One or two bloom sprays generally provided control of fruit infection not significantly (P > 0.05) different from that obtained with three bloom sprays. When applied during bloom, the fungicides fenbuconazole and benomyl + captan were superior to azoxystrobin and the biocontrol agent Bacillus subtilis in controlling fruit infection. Strategies for improving biocontrol activity of B. subtilis are discussed. © 2001 by The Haworth Press, Inc. All rights reserved.