Early Botrytis Rot of Grapes and Its Control

Early Botrytis rot of grapes is a new development in an old disease caused by Botrytis cinerea Pers. It is characterized by a brown rot of part of or most all grapes in a cluster from midseason to harvest in the absence of rain. Infection occurs through the stigmatic end of the flower at bloom time. There the fungus becomes latent until mid-season or later, when it resumes growth and rots the grapes. Effective control was obtained with benomyl applied as a water spray (1 lb 50% active/acre) or as a dust (15 lb of 10% dust/acre).