Grape vine withering and looking unhealthy

MikeIp

I recently bought a mature grape vine from a garden centre. When I purchased it a few leaves looked brown and withered but the rest of the plant looked healthy. A few weeks on having had a good water and feed half of the plant still looks to be struggling whilst the other is green and healthy.

I have included a few photos, could someone kindly help me identify the problem?

Many thanks!

BobTheGardener

It looks a little like spider mite damage and I think I can see some of the webbing at the tips (which is diagnostic) when I zoomed-in to your first photo:

They can be a problem in hot, dry weather, even outside.  They probably came with the vine as they prefer glasshouse conditions.  They are tiny and to see them you'll need to use a hand magnifying glass.  You can buy predator mites but those are usually used in greenhouses etc. and/or spray with something called SB Plant Invigorator which sort of glues them in place where they die, but isn't a pesticide as such.  They are resistant to most pesticides anyway (not that you'd want to spray those on something you are going to eat fruit from later!)

A regular spraying with a fine mist of water will help keep numbers down but I would use the SB stuff initially (as it's also a tonic and feeds the leaves) to get numbers down and then mist all of the vine regularly.  If that doesn't work, you could try the predators but I think they  are more sensitive to temperature than spider mites, so a cold night outside might kill them, although I've had great success with them clearing a conservatory where every plant was showing signs.

MikeIp

Many thanks for that quick and informative reply. I have purchased the SB Plant Invigorator and will give that a try. Thanks again!

BobTheGardener

Good luck with your vine @MikeIp !