Botrytis Blight of Peanut — Cultivar Susceptibility and Pathogen Fungicide Sensitivity1

Abstract

Abstract Botrytis blight of peanut, caused by Botrytis cinerea, was found in west Texas during the 2004 and 2005 growing seasons. Few data on the pathogen's sensitivity to fungicides commonly used on peanut are available, and there are no data on susceptibility of commonly grown peanut cultivars to this pathogen. Our first objective was to characterize the susceptibility of several peanut genotypes to the pathogen. Of the 53 isolates of B. cinerea collected from symptomatic plants in 2004, 34 were characterized as pathogenic, 3 were weakly pathogenic, and 16 were non-pathogenic based on lesion diameter 6 days after inoculation of detached leaflets of the cultivars Florunner, NemaTAM, and Tamrun 96. The susceptibility of eight additional cultivars and two breeding lines to two isolates of the pathogen (an aggressive isolate GilE-6 and a less agressive isolate DM1-R) was determined using a similar detached leaflet assay. The cultivars Flavorunner 458 and Valencia C had smaller lesions at 6 days after inocul...