EFFECTS OF MALATHION BAIT SPRAYS ON NONTARGET INSECTS ASSOCIATED WITHCORN IN WESTERN KAUAI, HAWAII

Malathion bait sprays were applied to border rows of sweet corn (Zea m aize L.) planted adjacent to papaya and cucurbit fields in Kauai, Hawa ii. The sprays were used to control the tephritid fruit flies, Bactroc era dorsalis (Hendel) and B. cucurbitae (Coquillett), that oviposit in to papaya and cucurbits but spend much of their time roosting on adjac ent border vegetation. Sweep-net samples in both treated and untreated corn plantings showed that significant reductions in overall species richness and species diversity occurred in malathion-bait treated corn . Numbers of beneficial insects (predators and parasitoids) were also reduced in treated corn, although this reduction may have resulted fro m prey depletion as well as direct mortality. Endemic insects were not well represented in the samples, and do not appear to be at risk from corn border spraying in western Kauai.