Bioassay for Dicarboximide Resistance in Botrytis cinerea . G. W. MOORMAN, Department of Plant Pathology, The Pennsylvania State University, 111 Buckhout Laboratory, University Park 16802. R. J. LEASE, and R. J. VALI, Department of Plant Pathology, The Pennsylvania State University, 111 Buckhout Laboratory, University Park 16802. Plant Dis. 78:890-891. Accepted for publication 7 July 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0890.

A simple, inexpensive bioassay successfully differentiated dicarboximide-resistant and dicarboxi-mide-sensitive isolates of Botrytis cinerea. Inoculum was placed directly into vinclozolin-contain-ing droplets on the growing tips of seedlings of the sunflower cultivar Sunspot. Resistant isolates killed fungicide-treated and fungicide-free seedlings in 3-7 days, whereas sensitive isolates killed only fungicide-free seedlings.