Vine disease??

[Winolady]

I have looked everywhere, and can't find a disease or anything that looks like what some of my vines have... the The Botrytis Fungus is as close as I can get. My vines are 4-year old Frontenacs. There was one vine that never did well since planting, and was the only one that was having these issues... I just thought it was a poor vine. Now several vines have this issue:

The shoots seem to grow OK, but the leaves and buds don't unfurl well, some get curled and brown, some leaf-tips and parts of the new grape-clusters die and turn brown, and the whole plant looks "thin" because the leaves aren't coming out right.

Here are some pictures:

The vine in the middle is affected:

The leaves that are able to expand look like this:

You can see dead shoot-ends, leaves that won't expand and unfurl and look yellowish:

Does anyone have any idea what might be going on? Thanks for looking!

 

[grapeman]

It could be from a heavy mite infestation. Look underneath the leaves for tiny insects (may need a magnifier). It could be something else, but I don't recognize anything in particular. You could have brought in one vine with mites and it has spread over time.

 

[djrockinsteve]

Look early in the morning at the leaves, top and under. Be patient. Look for anything moving or egg sacks. Grape an is probably correct. Let us know after a closer examination.

 

[Winolady]

Thanks for the replies! I looked this morning, but did see anything like a mite. But, after last night's rain, the spots and lesions on the vines were very much more pronounced, and I did some more researching.... I think I have anthracnose. The pictures and descriptions were very similar. This is what one extension site said:

Symptoms

On leaves, more or less circular, chocolate brown spots (1 to 5 mm in diameter) develop. The centers eventually become bleached and fall out, giving a “shot hole” appearance. Lesions along the veins may cause curling and distortion of the leaves as they expand. On shoots, spots are roughly oval, sunken and purplish-brown with gray centers and raised edges. Shoot tips may be killed and look burned. On older canes, lesions may extend into the pith and have thick raised edges and may be confused with hail injury.

Their pictures of the older, curled leaves are EXACTLY like mine.

 

[Winolady]

I went out and removed several vines that were totally infected, and severely pruned the rest... only the Frontenac had this. The St. Crois vines look beautiful.. As I pruned, it became more and more obvious that it has to be anthracnose... I could pick out the affected vines just by seeing the tiny brown dots that were all over the newest tiny leaves, and there were lesions on alot of the stems. Plus the rainy, damp spring we've had aggravates the spreading.

I hate to use chemicals, but I'm going to try a fungicide on the remaining Frontenac vines that don't yet appear to be infected. I'm sure they've been exposed, sbut maybe this will stop the infection.