Answer: The mysterious insect is the flea beetle, says Steve Reiners, Extension horticulturist at Rutgers University in New Brunswick, New Jersey. This common pest of eggplant in the mid Atlantic states overwinters on crop debris in the garden. The shiny, black 1/16 inch long adults emerge in spring and lay white eggs at the plant's base. The eggs hatch in a week and the larvae feed on plant roots for two to three weeks. The larvae pupate in the soil and the adults emerge to feed on eggplant leaves. There can be a couple of generations a year, but the problem is most severe in spring when plants are tender. There are a variety of controls for flea beetles. Growing eggplants under floating row covers reduces the damage to young, tender plants, says Reiners. Row covers must be removed when temperatures reach consistently into the 80_F range, but by then the plant has had a chance to get established, he notes. Mulching at transplant time with a four inch deep layer of hay or straw changes the microclimate environment and provides a physical barrier to the beetles. Flea beetles like hot, dry weather. The mulch keeps the soil moist and also seems to block the emerging flea beetles from reaching the plants, reports Reiners. Since the beetle overwinters on crop debris, fall cleanup is also important in keeping the population low. If these methods don't reduce the problem, you may have to resort to sprays. Sevin (carbaryl) and rotenone sprayed at transplant time and repeated as needed can control flea beetles, say Reiners. I've also seen diatomaceous earth, sprinkled around the base of new transplants and dusted on plant leaves, used to reduce flea beetle numbers, he adds.
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