SHORT- AND LONG-TERM EFFECTS OF FOREST SPRAYING OF CARBARYL (SEVIN-4-OIL®) ON STREAM INVERTEBRATES

Abstract

AbstractThe effect on stream invertebrates of carbaryl (Sevin-4-oil®) applied at a rate of 840 g A.I./ha for spruce budworm suppression in Maine was studied. Three streams in each of three different treatment areas were monitored: streams in areas sprayed with carbaryl for the first time, streams in areas sprayed 2 consecutive years, and streams in unsprayed areas.Initial postspray response was an increase in drift up to 170× in treated streams. Benthos samples showed significant declines among Plecoptera, Ephemeroptera, and Trichoptera on subsequent sampling dates. Plecoptera did not repopulate any treated stream by 60 days after treatment. Streams treated for the second consecutive year had very low prespray Plecoptera populations compared with those unexposed to carbaryl. Diptera, with the exception of Microtendipes, and Oligochaeta were unaffected.