What is this

Cellar Rats (ITB)
1

I have never seen this before. Only 3 small spots in the vineyard. Any idea what it is?

1000013848
10000138481920Ă—2560 440 KB

2

Nail Gall. Caused by a mite

3 Likes
3

Thanks

1 Like
4

And while we’re here, what is this?
It’s happened to this vine every year since we got it. The leaves come out properly and growth looks good and then after about 6-8 weeks the edges of the leaves start getting red. Eventually the leaf dies off and the process creeps along each shoot.

20250619_190355
20250619_1903551920Ă—1440 381 KB

5
  1. Does it always move from bottom up the shoots?
  2. Do the leaves also curl?
  3. What variety is the vine?
  4. Only this vine, but you have others planted as well that don’t exhibit this?
  5. Did you take soil samples before planting or petioles samples since?

This doesn’t look like potassium deficiency. Wondering if it might be Magnesium deficiency. I get the random leaf here or there from potassium deficiency but nothing systemic like your picture and description.

But if just the one vine and every year, more concerned that it could be a disease. First guess would be leafroll but that is just a guess at this point without more information.

6

I don’t have a full vineyard - just one vine of table grapes that came with the house (I think it might be Flame) and then put this one in a few years ago. I think it might be Autumn Royal, but either way it’s a purple table grape (not Concord) that I picked up at Lowes or Home Depot, truly nothing special in that sense. The Flame vine is healthy and vigorous, although it’s only got one grape bunch this year because I did a drastic rebalancing of the vine this past winter.

I’ve tried to look this up a few times and figured it could be a nutrient deficiency in the soil, so I’ve tried to supplement with extra fertilizer but that didn’t change anything. But no soil or other samples, no - this is just backyard gardening for me.

The leaves do curl a bit, downward/to the back side of the leaf. The discolouration is certainly more pronounced toward the base of each shoot and generally progresses upward. It’s not super strictly going up leaf by leaf, as a couple leaves near the ends of some shoots show some early signs of discolouration around the edge. Some seem to show small blotches in between the veins rather than starting at the edges, too.

Also, I am in Los Angeles and bud break for this vine was mid to late Feb this year, just a week or so behind the older/more established vine.

Thanks for the help!

7

Thanks for the additional information. Unfortunately, not sure it helps much.

The other vine isn’t very helpful as it is common for different varieties to have different times for bud break, bloom, etc. Different varieties can often respond differently to environmental conditions such as nutrient deficiency or water stress. That the other vine shows no symptoms doesn’t offer much information.

Since the vine was not purchased from a nursery, it can’t be assumed to be certified virus free. It is most likely vinifera, so all diseases are a possibility.

It could be a nutrient deficiency even though you have applied fertilizer if the soil pH is off or there is water stress.

That the older leaves are effected does appear to rule out leafroll (even though you noted the leaves do curl), which the source at the link below states appears randomly throughout the canopy. Crown gall and nutrient deficiency seem to be the most probable based on this aspect. If crown gall, there should be evidence on the trunk and you didn’t note that so assuming it isn’t crown gall.

So guessing that what you have is a nutrient deficiency, probably potassium even though yours looks different than what I see. I have different varieties so different appearance makes sense and potassium is a common deficiency. Also potassium deficiency might not be treated by fertilizer if the soil has sufficient amount that isn’t getting to the vine. You probably need to adjust the soil pH.

To state it again, I am guessing here. You need to test to verify. It could be a disease. I just think a nutrient deficiency makes more sense and would start there.

8

Thanks! I’ll check out my fertilisers and see if I have anything with potassium and go from there.