From: LFWILK Subject: Blueberries FAQ: Diseases,Pests,& Solutions Date: Mon, 18 Jul 94 00:06:33 -0500 BLUEBERRIES: DISEASES/PESTS & SOLUTIONS (FAQ) I'm just a novice, but I recently bought a house in New England that has 155 blueberry bushes on the property, so I'm trying to learn as much as I can about them. Before he left for the Pacific Northwest (to plant a cherry orchard), the previous owner (a very active 90-year-old with a real talent for gardening) gave me a few lessons on how to care for the blueberries (as well as the apples, peaches, plums, apricots, self-pollinating vegetables, herbs, roses, and several varieties of flowers on the property). He also gave me some articles and information he had collected on the subject. I thought I'd pass along the information that I've accumulated to-date. An excellent reference book on planting, caring for, harvesting, and using blueberries (as well as strawberries, raspberries, blackberries, cranberries, huckleberries, boysenberries, gooseberries, currants, etc.) is: "The Berry Book" by Robert Hendrickson, published in 1981 by Doubleday & Company, Inc./Garden City, New York. ISBN-0-385-13589-0. The following list of diseases/pests & solutions is a consolidation of information from: (1) primary sources are Robert Hendrickson's "The Berry Book" and his article "Blueberry Fields Forever" published in the July 1984 issue of "Country Journal"; (2) William Kreutzfeld 's article "Blue Magic" published in the August 1987 issue of "National Gardening"; (3) some tips provided to me by Mr. Eric Mattson (the 90-year-"young" gardener who has had lots of successful experience with fruits and berries); and (4) a few things from my limited experience with blueberry gardening. BLUEBERRY DISEASES/PESTS & SOLUTIONS 1. BIRDS - Birds love to eat blueberries and may even feast on your entire crop if you don't cover them with netting or use some other means to protect them. Mr. Mattson provided me with some plastic netting which seems to be effective and still allows sunlight to reach the plants. Be careful about leaving openings in the netting though, because birds may get through the opening and end up getting trapped inside the netting, become frantic, and possibly even die. 2. YELLOW LEAVES - Indicates problem with soil pH and/or drainage. Blueberries need acidic soil conditions and good drainage. Adjust the soil pH. Pine needles spread at the base of the blueberries seem to help with pH, drainage, and minimizing weed "takeovers" :-) Robert Hendrickson suggests applying iron chelate to the soil. Some people use miracid. 3. SHRIVELLED BERRIES - Indicates potential fungus disease. Berries shrivel, may turn purple or brown, and/or shoot tips die. Overfertilizing and/or using fertilizers with high nitrogen content creates an environment susceptible to some fungal diseases. All affected growth should be pruned to prevent the disease from spreading. Fungicides can also be used as a control. 4. ROTTING BERRIES - Potential causes may be fruitworms (small red worms that feast on berries) or fruit fly maggots which infect and rot the berries. Dusting berries with rotenone when they start turning blue helps prevent infections from fruit fly maggots. Robert Hendrickson also suggests controlling fruitworms organically with Beauveria bassica (a parasite fungus). William Kreutzfeld says that blueberry maggots and fruitworms are more common in Michigan, New Jersey, Maine, and North Carolina. Blueberries should not be left on the ground beneath the bushes (fruit fly larvae can survive the winter and infect the next season's blueberries; also, infections/diseases/parasites can be spread via the dropped blueberries). 5. FEW OR NO BERRIES - Potential causes include: overfertilizing, too much nitrogen in the soil, and/or inappropriate pruning. Another possibility is the viral infection "stunt disease" (typically spread by insects from nearby wild blueberries that are infected), which causes small leaves, few berries, and very little plant growth. Infected plants must be removed and destroyed (to keep from spreading the infection to other bushes). 6. BERRIES TOO SMALL - May be characteristic of the particular variety of blueberry, or the result of insufficient pruning. 7. ATTACK OF THE "LEAF-EATERS" - Aphids, leafhoppers, caterpillars, gypsy moths, and japanese beetles are potential culprits. Robert Hendrickson recommends "milky spore disease preparation" as an organic control of japanese beetles. Spraying with Sevin can be used to control leafhoppers, which in addition to leaf-eating can also spread disease (such as the stunt disease virus). Don't use Sevin during blossoming season because it kills the bees needed for pollination. 6. WILTING CANES - Wilting can be caused when Stem Borers bore through canes. Prune affected canes. Spraying with Sevin can be used to control Stem Borers, but should not be used when blueberry blossoms begin to bloom because Sevin kills the bees needed for pollination. I highly recommend obtaining a copy of "The Berry Book" which provides more extensive and more detailed information on both this subject as well as other aspects of growing berries. Please feel free to add suggestions from your experiences and knowledge on the subject.