Gummy Stem Blight of Cucurbits

Abstract

Gummy stem blight, caused by the fungus Didymella bryoniae as the sexual stage (perithecia giving rise to ascospores) and Phoma cucurbitacearum as the asexual stage (pycnidia producing conidia), is a common disease of all major cucurbits and is present wherever they are grown. Both stages of the pathogen can occur on infected tissue during the season, but they vary in importance as inoculum sources. The disease has been reported in New York since the early 1900s. Gummy stem blight refers to the foliar and stem-infecting phase of the disease, black rot to the fruit rot phase (see fact sheet, page 732.10, Fruit Rots of Squash and Pumpkins).