White substance on my Concord Grapes - Ask Extension
County resident has 16 ft x 8 foot wide grape arbor . Most of the grapes located on bottom of vines 4ft of vines have been infected. What is our Pr...
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White substance on my Concord Grapes #201437
Asked July 22, 2014, 2:53 PM EDT
County resident has 16 ft x 8 foot wide grape arbor . Most of the grapes located on bottom of vines 4ft of vines have been infected. What is our Problem? and What do we need to do to control?
The fruit seems to be affected not the leaves or vines. There were no brown spots or white substances on the leaves brought into the extension office.
Tuscola County Michigan
Expert Response
It looks very much like downy mildew fungus, but it is hard to verify this without a close-up inspection. Several fungicides are available to combat this fungus, but many will not come in convenient packaging for homeowner price range or application equipment. Check labels of products available locally to see if grape downy mildew is included on the listing of diseases controlled.
Moisture management is also important. When irrigation the vine or nearby plants, keep the water away from the foliage and shoots of the grape.
Moisture management is also important. When irrigation the vine or nearby plants, keep the water away from the foliage and shoots of the grape.
