Symptoms: The disease can infect the leaves, fruits, new shoots, petioles, fruit stalks, axes, tendrils and inflorescences of grapes, especially the tender parts.
The leaves begin with pinholes, reddish-brown to dark brown spots, and there are faint halo around them, and then gradually expand to form nearly round or irregular lesions, with a diameter of 1 ~ 4 mm, a gray center, a little depression, and dark brown or purple edges. In the later stage, the mesophyll in the middle of the lesion withered and cracked, and the leaves appeared perforation.
Harmful symptoms
Generally, the third and fourth leaves of new shoots come first. At the time of onset, the lesion on the leaf surface is irregular, generally 3 ~ 4 mm in diameter, with a gray center, light brown around it, and some dark brown, with obvious boundaries with healthy parts. Sometimes there are more than 30 lesions on a leaf, connecting the large and small lesions together. On sunny days, the diseased spots are brittle, and most diseased spots will fall off and make holes, leaving traces around the holes, which will eventually lead to the leaves falling off.