Prime Time Newspapers

Week of May 26, 2003

Submitted by Calvin Finch, Ph.D., Manager, Conservation Division, Water Resources & Conservation Department, SAWS, and Horticulturist

 

BLACKBERRIES AND OTHER FRUIT

 

            The late freeze we had this spring destroyed much of the Hill Country peaches, plums, and blackberry crops for the year and some of our backyard fruit in San Antonio but not all of it.

            Blackberries are an easy crop to grow in San Antonio; they yield well the second growing season. Brazos, Rosborough and Womack are the old reliable varieties. Jerry Parsons, Texas A & M Horticulture Specialist in San Antonio, likes the Kiowa variety, which was recently released by Arkansas. There are also some thornless varieties including Arapaho and Navaho. They produce less fruit and mature later than the popular thorned selections but are desirable because the thornless stems make them easier to pick and pruning is infinitely easier. After harvest the old canes that bore the fruit (floricanes) should be cut to the ground and removed. The new canes (primocanes) then grow to be in place for next year’s crop.

            Blackberries, especially the thorned varieties, are very aggressive and spread quickly. You never want to plant them against a fence or any place where they cannot be controlled. To start your blackberry bed, obtain roots or plants and place them in full sun. Provide some slow-release lawn fertilizer once per year and an occasional iron treatment, and they will provide berries every year in April and May.

            Peaches and plums will load the tree with fruit in a typical season. So much fruit, in fact, that it is best to thin them to one fruit per 4 to 6 inches of stem. Thin when the fruit is dime-size to influence eventual fruit size. Thinning the fruit also allows more light and air movement around the remaining fruit to reduce the incidence of disease. Thinned trees also are better able to physically support the fruit and there is less limb breakage.

            If your crop is like mine, this year the freeze took its toll. Several of the early blooming peaches and plums have very few fruit. The fruit that remains should be plenty large, if they escape the insects and squirrels. You may also have some fruit that is freeze damaged. If the embryo was damaged the fruit grew awhile but then shriveled and dropped. Other specimens are continuing to grow but are very gnarled. The indentations and scar tissue are formed where the low temperatures killed some of the cells on the immature fruit but not all of it. The fruit with such damage may survive until harvest time and can be used but it is not appetizing.

            The freeze damage resembles stinkbug damage which is also prevalent now. The symptom is described as cat facing. The stinkbug and other cat facing insects inject their digestive juices into the fruit and suck out the soup to keep themselves alive. The action kills the surrounding cells just like the freeze damage. The killed area does not develop any further and appears as a “puckering” or cat facing. Recent stink bug damage is recognized by a bubble of clear sap that emerges from the penetration hole.

            If you have not been spraying your fruit every week or 10 days this spring, you probably have extensive damage from insects. I use malathion every week from blossom fall to about two weeks before harvest when I shift to carbaryl (Sevin). Most malathion formulations seem to require seven days between the last spray and harvest, Sevin is usually just one day. Captain is a fungicide that you can use with the insecticide to reduce disease pressure. It requires 0 days between application and harvest.

            It is still very difficult to control disease and insects with organic controls. The neem oil products and sulfur can be used. I had some success with the new Green Light product “Bioganic” in controlling beetles on potato plants and aphids on cyclamen. It is available in a hose-end version that may have a role in an organic spray program. The product uses thyme, clove and sesame oil as active ingredients. Wintergreen is also added. Even if the insects are not controlled, it smells good!

            Review the labels of all pesticides every time you use them. Even organic controls can be dangerous and you must follow the label instructions.