River,

Blackberries are prone to several types of fungal infections on the leaves, especially in hot and humid weather.

Look at the white spots. Do they have any sort of darker ring or border around the white? Maybe some sort of brown or purplish discoloration that sort of encircles the white areas? And, check out the stems/branches. Do you see any sort of discoloration there? And, if so, is the discoloration circular? With a better description of the spots, we probabaly can figure out what it is.

If it is only a white powdery looking growth, it may be powdery mildew. However, if you have any necrosis (tissue death) within those white areas, it is probably something more serious than powdery mildew.

Also, blackberries get some of the same foliar diseases as tomatoes and roses. Does it resemble anything you've seen on the leaves of either one of those kinds of plants?

Dawn

Did a little googling and found it!! I copied and pasted this:
Elizabeth Wahle, Extension Specialist Horticulture, Fruits, and Vegetables at the Edwardsville Extension Center, said she has received several calls about blackberry and raspberry fruit problems.

The fruit is usually described as having bleached areas in the fruit or as having hard areas, or areas on the fruit that look dried up. Because of the intense heat and low rainfall recently, all these symptoms are most likely the result of heat damage. The fruit are literally cooking on the plant. Maintaining uniform soil moisture is very important during fruit development in order to help the plant cool itself through evapotranspiration. In addition, overhead sprinklers can be used to cool fruit during hot summer days. This is a common occurrence during the heat of summer, and unfortunately, once the fruit cooks, it can't be uncooked. The fruit is safe to eat, ­just not as palatable.

She has added that stinkbug feeding also results in bleached areas of the fruit. Heat damage tends to be on the "sunny-side-up" side of the fruit, and usually encompasses a larger area of the fruit. Stinkbug damage can be all around the fruit, but it tends to be individual droplets that are bleached as opposed to whole areas.

Stinkbug damage is pretty common around here. The local pick-your-own had a lot of it the year I picked them, and I have a small percentage with those light, brownish individual "droplets" this year.

Stinkbugs are a horrible problem here, but I've never had them on berries. In our yard, they prefer tomatoes. (Wouldn't you just know it?) Do they eat just any old tomato? No, no, no. Their favorite tomato is one of my favorite tomatoes--Black Cherry. It makes me wonder if they chose their "targets" by flavor because they tend to be worst on some of the plants with the absolute best-tasting fruit.

Stinkbugs are hard to control. They pierce the fruit and suck out its juices and at the same time they inject a little "poison" (not deadly, just yucky tasting) that causes those little blotchy spots. I don't know how it affects the flavor of the berries, but it can make tomatoes taste sour---not so much if there's just one or two of those little spots, but if there are several of them.

I do my best to handpick the stinkbugs and flick them into a container of soapy water where they then drown. They like to hide deep inside the plant foliage, but if you hit the plant with water from the hose they often will climb to the top of the plant to dry off and then you can handpick them. Some people spray their plants, fruit and all, with a non-toxic kaolin clay product called Surround, which apparently makes the fruits less attractive to the stink bugs. You just wash the clay off the fruit when you harvest it....it just leaves a dusty whitish film over any part of the plant with which is makes contact.

Some people claim to have had some success in repelling the stink bugs by spraying their plants with a water and vanilla mixture. I've never tried it though. I cannot even imagine how much vanilla and how much time it would require to spray 140 tomato plants. (sigh) Some people have very good luck covering their plants with floating row covers early in the season before stinkbugs appear.

Most people here consider their gardening season to be "over" when the stinkbugs arrive, but I battle them to the extent that I can. I don't know of any predator that targets them (although surely there must be one). My farmer friends who use chemical pesticides tell me that nothing works very well on them. One says liquid Sevin works somewhat to control them in his large vegatable garden, although he doesn't think it is extremely effective.....and he knows it kills off all his beneficial insects and bees, which is a real problem for him.

I think I read somewhere that some people have had luck with a bio-insecticide called Spinosad but I haven't tried it on stinkbugs. I have used Spinosad as an organic fire ant control and it has been pretty effective (impressively so) on them. The spinosad I use for fire ant control is a granular product but the one you'd want for stinkbugs would be a liquid--you can get it in concentrate form or in a ready-to-use spray bottle.

I don't know if this is any consolation, River, but in a "normal" year (if there is such a thing), I usually don't see stinkbugs here in large numbers until late July or early August. So, if your blackberries normally ripen earlier than that, you shouldn't have this problem every year. Unfortunately in this most bizarre year, the stinkbugs showed up in huge numbers in mid-May here. I have read similar reports from all across the nation and some people who have NEVER had stinkbugs in their gardens in relatively cooler parts of the country also have them in great abundance this year.

It is my understanding that both sunflowers and millet are a great trap crop for stinkbugs, and I am thinking about preparing an area immediately adjacent to the garden this winter so I can plant those two trap crops next spring and see if they make a difference.

And, even though I've had a moderate stinkbug problem some years, and no stinkbugs at all other years, many people have similar problems with and damage from the closely related leaf-footed bugs and blister beetles every year.

Dawn