Gummy Stem Blight

Causal Agent: (fungus ‑ Didymella bryoniae)

Early symptoms are round black, wrinkled spots on young leaves and dark sunken areas on stems.  Early infection usually develops from  contaminated seed and can be visible on transplants [wmd12.jpg]. Often, infected transplants will have lesions on the the stem [wmd62.jpg].  On older leaves in the field, irregular brown to black spots develop between leaf veins [wmd3.jpg].  Leaf lesions will expand [wmd63.jpg], eventually resulting in the death of leaves [wmd64.jpg].   As the disease progresses, older stems near the crown, most commonly near a leaf petiole or tendril, split and a light brown gum oozes from the watersoaked areas [wmd11.jpg].  The crown may also be infected and produce a brown ooze [wmd61.jpg].  Infected runners die, leaving fruit exposed [wmd60.jpg].  Fruits are not usually affected.  Protective fungicide applications are needed for control. Resistance to benomyl and thiophanate-methyl fungicides have occurred in some growing areas, so these fungicides are not recommended.