1. Spray damage (Phytotoxicity-Leaf burn)
Sulfur, copper, and copper sulfate (Bordeaux mixture) fungicides can burn the foliage of certain grape varieties (Concord). Read the label of the product you intend to apply to determine the percentage of the active ingredient and any cautions that accompany its use. Do not use pesticides on stressed plants.
2. Drought/Environmental Damage
Caused by lack of moisture and hot, dry temperatures.