I have some grape vines this is the first year they have had grapes and...

Asked July 6, 2014, 1:47 PM EDT

I have some grape vines this is the first year they have had grapes and theyare loaded this year but they are rotting instead of getting ripe

Sevier County Tennessee grapes

1 Response

Several different rots may occur in grapes in East TN. Perhaps the most common one is called black rot. With it, the berries turn dark brown to black, shrivel and dry up on the cluster and end up looking like raisins. Depending on the variety of grape, damage can range from minor all the way up to all of the grapes in a cluster being affected. The mummified berries do not drop from the cluster and may remain on the vine for the rest of the summer and over the winter months. On the leaves, you might see brownish, irregularly-shaped dead areas that will be about 1/4 inch in diameter. Often, there will be black dots in the center of these lesions. Immunox is probably the best fungicide to spray for this disease, however, the first spray should be applied at bloom and repeated at weekly intervals for about a 6-week period. It is probably too late to do anything this summer if black rot is the problem. Anthracnose, also called bird's eye rot because of the round white to gray circular rotted area with a dark center that looks similar to a bird's eye. Anthracnose is not as common as black rot. Control is best achieved using a dormant spray of lime sulfur followed by a similar spray program as described for black rot. You can look up black rot and anthracnose online to see pictures of the fruit and foliar damage. Later in the growing season, we will start to experience some fruit losses to bitter rot, sour rot and ripe rot, but t is too early for them at this time.