- Brown leaves
- Blighted vines
- Spotting leading to blight
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.
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.
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.
Active Ingredients include: Chlorothalonil, Thiophanate-methyl
