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For the last 2 years my (10 yr old) grape vine has developed a disease which I believe to be powdery mildew. Last year I sprayed early with Bayer Fungus Fighter a few times but no improvement. This year I've been spraying very 2 weeks but it's looking even worse than usual at this time. Any thing I can do apart from ripping it out?

The photo is typical of the entire plant. Brown patches on leaf edges, white bloom on new leaves, curling leaves, deformed shape, leaf colour dull green etc.

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Background info - location Cotswolds SW England. It's an ornamental vine but don't know specific variety. I bought the house 3 years ago, neighbour reckons vine could be 10 yrs old. It grew vigorously first 2 years but got mildew both years and lost leaves in early August.

Soil by house not great so have added compost, mixed with some miracle grow, to base of plant in mid May and have been watering regularly

Alan Johnston
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No, it is clearly not powdery mildew.

Looking for Bayer Fungus Fighter, I have doubt that it is useful for grape vine. I don't recognise the substance names (for grape vine) not I see indication that it is usable on grape vine.

So don't use it. It could be toxic for grape vines.

A photo of the rear part of leaves could help, but I think it could be:

  • there is shortage of fertiliser or maybe over-fertiliser. Often it is difficult to tell (but for few substances). Note: Fungus Fighter could make things look worse. You should know if you fertilised or not.

  • Mites (check on bottom part of leaves, if you see felt like substance, or if you have a lens and you see mites you have the silver bullet. But usually new leaves should not have such form.

  • Problems at bud time. Mites but also freeze, at bud time, create similar leaves. Again: new leaves should be normal, and you will see that the leave stem usually is shorter and darker. Which doesn't seem the case.

  • Wood disease. Often it cause similar leaves, but the branches seems OK, so I don't think it this. Note heavy froze in winter could cause similar problem (froze at graft point, so reduced sap).

  • Toxicity: herbicide or pesticides used for near plant could cause toxicity.

Note: there is many possibilities, but all related to sap and circulatory system of the vine, so with similar symptoms. I really doubt is it a fungus (but ev. wood or root fungus)

Giacomo Catenazzi
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  • Thank you so much for your response Giacomoa. It feels great to have some thoughtful help with this :-) – Alan Johnston Jun 03 '17 at 09:34
  • Giacomo - I added some photos and background info to my post. – Alan Johnston Jun 03 '17 at 10:15
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    • Fertiliser: The soil by the house is not great so I added compost mixed with some miracle grow to the soil at base of plant a few weeks back but no change.
    • Mites - Can't see any but will look some more • Bud damage: I agree I don' think it's frost damage as the newest leaves are still looking miserable as they appear • Wood disease: Yeah branches look fine to me • Pesticides: We don't use pesticides and our other plants are thriving, so unlikely to be that.
    Do let me know if you get any other ideas from the photos and sincere thanks once again     – Alan Johnston Jun 03 '17 at 10:15
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miteOk I have the answer to my grape vine problems.

Its spider mites for sure - see photos

nymph? I have applied Neem oil solution liberally twice in a week but still have mites. Going for Bug Clear Ultra now (acetamiprid) Thanks Giacomo for helping me realize that this wasn't another mildew infection

Community
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Alan Johnston
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Check the PH. Growing next to brick or concrete can cause lime to leach into the soil raising the PH too high. After that, a number of problems could start to manifest that could make it look like something else is going on. My guess is PH is too high along with possibly being too wet for the roots.

stephencarlsbad
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