Key Features
- Brown leaves
- Blighted vines
- Spotting leading to blight
Symptoms
Lesions are usually brown but can turn black under wet conditions. Leaf spots can continue growing, and the fungus can continue down the petiole and into the stem.Small black fruiting bodies may be seen within the lesion.
Biology
This fungal pathogen begins as a leaf spot, but can continue on to grow into the petiole and then into the stem, causing cankers that result in the sudden blighting of the plant. The fungus overwinters in leaf and stem debris.
Management Recommendations
Improve air movement and speed up drying of leaves by thinning the plant. Prune out and destroy infected vines to reduce inoculum. As this is a foliar pathogen, removing the vines at the end of the season, will reduce the disease. It may cause a reduction of flowering of those varieties that bloom on old wood, so it may take two years for a vine to return to its former appearance.
Effective Pesticides
Active Ingredients include: Chlorothalonil, Thiophanate-methyl
Resources
- Not satisfied with ID? Contact the Purdue Plant and Pest Diagnostic Lab
- Sign Up for the Purdue Landscape Report
