A broad evaluation of B.t.i. for black fly (Diptera: Simuliidae) control in a Michigan river: efficacy, carry and nontarget effects on invertebrates and fish.
Efficacy for black fly control, carry and nontarget effects of B.t.i. (Teknar HP-D), applied in the Betsie River, Michigan, were studied in June 1988. Black fly mortality was high (approximately 100%) for a 2,200 m stretch downstream from the application site, declined to 30% at 3,200 m, and was nil at 4,500 m. Drift of black flies greatly increased after application at a downstream site, but did not change at an upstream site. There were no detectable nontarget effects of B.t.i. application on: 1) invertebrate macro- or micro-drift; 2) numbers of invertebrates in benthic Surber samples; 3) mortality or feeding of drifting and nondrifting insects; 4) growth or mortality of caged Stenomena sp. larvae; 5) invertebrate functional group composition; 6) mortality or weight change of caged rock bass; or 7) fish numbers, species composition, length-weight (rock bass only) relationships or rock bass diet. Sampling of Rheotanytarsus sp. midges on natural substrates indicated low (27%) mortality owing to B.t.i. at only 100 m downstream from the application site, with negligible mortality at all other downstream and upstream sites. This information, combined with no pronounced changes in numbers of midges in macro-drift after application, indicated that midge populations were not adversely affected by B.t.i. in the study.
Merritt
R W
RW
Department of Entomology, Michigan State University, East Lansing 48824.
Walker
E D
ED
Wilzbach
M A
MA
Cummins
K W
KW
Morgan
W T
WT
D000704:Analysis of Variance; D000818:Animals; D001413:Bacillus thuringiensis / Q000254:growth & development / Q000502:physiology*; D002683:Chironomidae / Q000254:growth & development; D005247:Feeding Behavior; D005399:Fishes / Q000254:growth & development*; D005618:Fresh Water; D007313:Insecta / Q000254:growth & development; D008824:Michigan; D010572:Pest Control, Biological; D012843:Simuliidae / Q000254:growth & development / Q000382:microbiology / Q000502:physiology*; D014867:Water; D014871:Water Microbiology
D014867:Water