SUSTAINABLE MANAGEMENT OF BOTRYTIS BLOSSOM BLIGHT IN WILD BLUEBERRY (VACCINIUM ANGUSTIFOLIUM AITON)

Abstract

Botrytis blight is an important disease of wild blueberries with control dependent on fungicide usage. Given concerns over human health, environment, and fungicide resistance, field and laboratory experiments were conducted during 2015 and 2016. Laboratory radial growth expansion assessments of Botrytis cinerea isolates on media amended with pyraclostrobin, boscalid, penthiopyrad, cyprodinil, and fludioxonil were conducted. Field trials investigating the susceptibility of four phenotypes at different flower stages as well as burning, lime sulfur and the use of biofungicides and their rotation with a botryticide were undertaken. Resistance towards cyprodinil, pyraclostrobin and boscalid in B. cinerea isolates was detected. No shifts toward resistance to penthiopyrad or fludioxonil were detected. Vaccinium angustifolium was susceptible while V. myrtilloides was less susceptible. Floral stages F6 and F7 were susceptible while F5 and F8 were less susceptible. Burning and lime sulfur demonstrated disease control, and biofungicides used in rotation with Switch® provided Botrytis blight control.