A prospective study of the effects of ultralow volume (ULV) aerial application of malathion on epidemic Plasmodium falciparum malaria. III. Ecologic aspects.

The effects of aerial ultralow volume (ULV) malathion on selected species of nontarget animals in Haiti are reported. Mortality of certain groups of insects such as bees, flies, beetles, and butterflies was observed immediately following spray application. Minor fish mortality occurred only in shallow water exposed to direct spray. The brain acetylcholine esterase levels of living fish, tree lizards, birds and bats collected from treated areas were not significantly reduced. No ill or dead animals, besides the few fish, were seen even when maximum exposure occurred. Only minor changes in the feeding behavior of some insectivorous birds were observed. The relative bird density decreased substantially for only one species during the study, and other factors besides treatment were considered to be the reasons for the decline. Aerial applications of ULV malathion at dosages sufficient to dramatically reduce anopheline populations did not significantly affect nontarget vertebrates in this tropical environment.