Ghadames
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Something Is Eating New Emerging Grape Leaves

I first thought that maybe my grape vine is suffering from a fungal infection, but it seems to me that it's a bug or something that is eating the emerging new leaves on the canes.

I was told that it could be caterpillars, so I applied an insecticide last weekend, bacillus thuringiensis sub-species kurstaki (will do again today), but I still have the same problem, except the old leaves have not been touched (I think). I've only seen one caterpillar on a cane during night time throughout the summer. I can't find dead bugs on the ground.

I don't see any bugs in large numbers or anything visible on the new leaves. Notice the web-like white stuff on the leaves. What bug is causing this and how can I get rid of it?
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AnnaIkona
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Looks more like some fungul disease than a pest to me.

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applestar
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Have you checked for slugs? They feed at night.

Ghadames
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It was infected with (what clearly appeared to be) Phomopsis Cane and Leafspot disease last year. So I cut all the trunk and removed everything. This year, I applied Captan on the trunk and new canes started to show up, but the holes are still there. The actual canes look green and healthy, so it can't be Phomopsis Cane and Leafspot disease again. No, I don't see slugs and anything special day or night.

If it's disease, what could it be and what should be done?

AnnaIkona
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Before we try to get rid of the disease, as this may be tricky, try to get rid of small insects and bugs. They can be on there, but you can't see them. Spray with insecticide soap spray (can be bought at a local home and hardware store for like $5) and spray all the leaves, on top and on the bottom.

If the damage is still being caused, the problem is most likely a disease.

Ghadames
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I applied an insecticidal soap a few days ago, but the new leaves are still growing in the same manner. In the night time, I noticed that there are a few earwigs on the grapevine, some spiders and tiny white bugs (or eggs) that could have been whiteflies.

However, I'm starting to think it is a disease. I've uploaded a few more pictures of the new emerging leaves, and you can clearly see that there are black spots on the edges of the leaves. What disease would causes this?

I've removed the entire plant in early spring and allowed it to regrow, but it is still suffering from something. Can a disease survive inside a grapevine? I'm starting to get fed up with this vine, and I'm thinking about killing it in fall.
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applestar
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I came across this guy munching on my grape leaves. I believe it is a Virginia Creeper Sphinx moth caterpillar.
I think I'm going to let it stay -- it's almost ready to pupate and have not caused too much damage -- certainly not enough to have me looking for it. :mrgreen:

Image
Hornworm caterpillars: The big cats of the vineyard | MSU Extension
https://msue.anr.msu.edu/news/hornworm_c ... e_vineyard
Virginia creeper sphinx moth caterpillar is a more typical hornworm, bearing a distinct horn on the tail end

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rainbowgardener
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If it is a hornworm, they are amazingly difficult to spot for how big they are, very well camouflaged! Look closely. Also look for big black barrel shaped droppings; they will lead you to the caterpillar.



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