You might look at this link and see what information you can glean from it. If you click on the pictures it will take you to links for recommendations for treatment.

Anna

Here is a link that might be useful: Cornell University Berry Diagnostic Tool

Jessaka,

First, I'd try to figure out what is causing it. Do you see aphids, psyllids, leafrollers or leaf hoppers or any other pest on those plants? (Don't forget to look on the undersides of the leaves.) If you have any of those pests, they may be causing the leaf curl. A sharp spray of water, especially to the back of the leaves, every couple of days will dislodge them and annoy them enough that they'll go away.

Secondly, are you seeing any other symptom on the leaves like discoloration or puckering of the tissue? If so, you might have a little viral thing going on or maybe raspberry leaf curl, which is serious on raspberries but less so on blackberries.

Third, if they just started to curl on the hot days and they then improve a little in the evening when the sun is setting and then curl worse the next day, that's a heat stress thing. When the heat stress lessens, the curling will go away on its own.

Fourth, a soap spray might be OK today if you have a heavy infestation of aphids, but otherwise I wouldn't use it until after this weekend's heat wave has passed. At extremely high temperatures, soap sprays (and all oil-based sprays like neem or citrus oil or veggie oil sprays) burn foliage and can kill plants. Also, soap sprays only kill the aphids on the plant at the time you spray. It has no residual value.

If you do spray, don't spray in the heat of the day or when there is sunlight on the foliage. Try to spray early in the day or late in the day, let the soap spray stay on a little while to kill the aphids, then hose it off so the foliage won't burn.

I've never seen leaf curl on blackberries except in books, but then our climate seems hard on everything this year with all the swings from hot to cold and wet to dry and back again.

Dawn

yes, there are bugs under the curl. thanks for the information.