LABORATORY AND FIELD-EVALUATION OF NEEM FOR THE CONTROL OF APHIDS (HOMOPTERA, APHIDIDAE)

Laboratory and field trials with formulated neem seed oil (NSO) and neem seed extract (NSE) demonstrated that these materials are effective aphicides. NSO sprays to intact plants in the laboratory resulted in significant reductions in numbers of green peach aphids, Myzus persicae (Sulzer), on peppers and rutabagas; currant-lettuce aphids, Nasonovia ribisnigri (Mosley), on lettuce; and strawberry aphids, Chaetosiphon fragaefolii (Cockerell), on strawberry. NSO reduced aphid numbers in a dose-dependent manner, with estimated concentrations for a 50% reduction in aphid populations (EC50) ranging from 0.2 to 1.4%. Under field conditions, NSO and NSE treatments were as effective as the botanical insecticide pyrethrum for control of aphids on pepper and strawberry, but ineffective for the control of aphids on lettuce. The effectiveness of neem appears to be influenced by the host plant, the aphid species, and weather conditions.