Hi,
I’m new to growing grapes. Could people please identify these two different diseases on my grapes? Each leaf is from a different grape vine. Only a few of my vines are infected. Once identified, how do I treat and prevent them in the future? Preferably organic means, if possible. I’m in zone 5b/6a, these are one year old vines.
Thanks!
Janet, I very much doubt if either one is caused by a disease.The first picture looks like a burn. The second looks like some type of chlorosis. Nutrient toxicities and deficiencies could be your problem. Depending on how much of the leaves are displaying this, a soil test might be advised, if you have not already done so.
They both look like a nutrient issue to me. Look up pictures of nutrient deficiencies and compare with your leaves.
The first picture isn’t Pierce’s disease?
Your zone is very likely too cold for that disease.
Pierces’s disease will show a yellow border between green and brown tissue. After the leaves drops the petioles will remain attached giving the vine a matchsticks appearance. According to the map, I am supposed to be in a location where it is rare but I am seeing it more and more.
http://www.plantmanagementnetwork.org/pub/php/research/2008/pierces/
