G. cassandrae can also cause a twig blight and leaf spot, but only the rotting of fruit in storage is economically important. Symptoms End rot typically begins at the blossom end of the berry. The rotted tissue is soft, watery, and clearly delineated from sound tissue. Gas formed during the rotting process bloats the berry and makes it elastic to the touch. If pressed too hard, however, the berry bursts.
Berries eventually collapse and turn yellow or brown.
Photograph by Steve Vicen. The fungus overwinters in old bark and plant debris left after harvest. It also resides in apparently healthy vines throughout the year. G. cassandrae can be isolated from new shoots, blossoms and the blossom end of young fruit, but rot usually occurs only after fruit are damaged or start to senesce. Infection probably also takes place when fruit are damaged during harvest.