Natural controls, including natural enemies — ladybird beetles, lacewings, syrphid flies, and parasitic wasps — usually bring aphid populations under control shortly after they become noticeable.
Residents should search the aphid colonies for these natural enemies. High numbers of these beneficial insects usually indicate that aphid problems are being controlled without intervention. Do not apply chemical insecticides on plants to control aphids, since these will also kill off the beneficial insects and the aphid population will come back with a vengeance.
Ray Ridlen is an agriculture/horticulture educator for the Oklahoma County Extension Service. His column addresses frequently asked horticulture questions. For more information, call 713-1125.