Grapevine leaf discoloration - Ask Extension
Hi,
I am propagating from a set of grape vines that have been in my family for generations. The plant has been doing wonderfully this summer, but j...
Knowledgebase
Grapevine leaf discoloration #878310
Asked July 22, 2024, 4:25 PM EDT
Hi,
I am propagating from a set of grape vines that have been in my family for generations. The plant has been doing wonderfully this summer, but just today I noticed some discoloration on the oldest leaves. I check the plant thoroughly daily, so this is a recent development. I just recently removed a sweet basil plant that was infected with fusarium wilt that was about 8 feet away in a separate planter. Is this something to be concerned about?
Hamilton County Ohio
Expert Response
Hello Marshall,
first let me say how sorry I am for being so late in answering. Somehow your question got misplaced in my emails.
I am glad to tell you that you most likely do not have fusarium or verticillium wilt. Neither of those diseases tend to affect grapes very often. It would be very strange and they present differently.
I think you have grapevine leaf rust. It is caused by a fungus that needs two hosts (think cedar/apple rust). You can use grape fungicides to help deal with it. Something containing sulfur, copper or captan should help. Since your vines don’t look like you will be producing a harvest, you don’t need to worry about the 30-45 days pre harvest warning that tells you it could delay fermentation.
https://utia.tennessee.edu/publications/wp-content/uploads/sites/269/2023/10/W790.pdf
https://www.canr.msu.edu/news/late-season-grape-diseases-and-fungicides-on-fermentation
This one looks just like your picture:
https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/plant/grapevine-leaf-rust#:~:text=Grapevine%20leaf%20rust%20is%20caused,in%20damage%20to%20grape%20crops.
Hope this helps, again sorry for being so late.
first let me say how sorry I am for being so late in answering. Somehow your question got misplaced in my emails.
I am glad to tell you that you most likely do not have fusarium or verticillium wilt. Neither of those diseases tend to affect grapes very often. It would be very strange and they present differently.
I think you have grapevine leaf rust. It is caused by a fungus that needs two hosts (think cedar/apple rust). You can use grape fungicides to help deal with it. Something containing sulfur, copper or captan should help. Since your vines don’t look like you will be producing a harvest, you don’t need to worry about the 30-45 days pre harvest warning that tells you it could delay fermentation.
https://utia.tennessee.edu/publications/wp-content/uploads/sites/269/2023/10/W790.pdf
https://www.canr.msu.edu/news/late-season-grape-diseases-and-fungicides-on-fermentation
This one looks just like your picture:
https://www.agriculture.gov.au/biosecurity-trade/pests-diseases-weeds/plant/grapevine-leaf-rust#:~:text=Grapevine%20leaf%20rust%20is%20caused,in%20damage%20to%20grape%20crops.
Hope this helps, again sorry for being so late.
