Hi everyone! I'm new on this forum, looking if you can help me. Some grape leaves started to look weird. Can you please help me identify and handle the problem? I'll probably need to spray them.
Looks like a viral disease, may be Grapevine leafroll virus. Compare with Grapevine leafroll-associated virus 3
It doesn’t appear to be leaf roll virus. It looks like powdery mildew. This can explain the chlorosis (yellowing) of the leaves. If left unchecked, it can severely impair or kill the vine. Regular schedules of mildew spraying may help. I’d start with Stylet oil, 1.5 ounces per gallon of water. Coat both upper and lower leaf surfaces early in the morning or after sunset. Don’t apply during bright sun, leaves will burn. Mildew can become resistant, so it pays to do some research. JMS Organic stylet Oil can be purchased online. Made from paraffins. I don’t know where you are but I know Canada has different/strict laws. “Surround” is also safe and effective. It is simply kaolin clay which will help. It has the side benefit of cooling the leaves (which may or may not benefit your grapes dependent upon your climate) and resists certain pests. Good luck!
