Non-target effects of microbial insecticides used against mosquitoes and black flies

Mosquito Larvae Leaf  Web

Mosquito Larvae

Several studies have been conducted over the past 15 years on the non-target effects of microbial insecticides (B.t.i., Bacillus sphaericus) used against mosquitoes and black flies. The results of these studies are discussed in the publications below.


Merritt, R.W., E.D. Walker, M. A. Wilzbach, K. W. Cummins, and W.T. Morgan. 1989. 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. J. Amer. Mosq. Cont. Assoc. 5: 397-415.

Merritt, R.W., M.S. Wipfli and R.S. Wotton. 1991. Changes in feeding habits of selected non-target aquatic insects in response to live and Bacillus thuringiensis var. isralensis de Barjac-killed black black fly larvae (Diptera: Simuliidae). Can. Entomol. 123: 179-185.

Wipfli, M. S. and R. W. Merritt. 1994. Disturbance to a stream food web by a bacterial larvicide specific to black flies: Feeding responses of predatory macroinvertebrates. Freshwat. Biol. 32: 91-103.

Wipfli, M. S., R. W. Merritt and W. W. Taylor. 1994. Low toxicity of the black fly (Diptera: Simuliidae) larvicide Bacillus thuringiensis var. israelensis to early stages of Brook trout, Salvelinusfontinalis; Brown trout, Salmo trutta; and Steelhead trout, Onchorhnchus mykiss following direct and indirect exposure. Can. J. Fish. Aquat. Sci. 51: 1451-1458.

Wipfli, M. S. and R. W. Merritt. 1994. Lethal and sublethal effects of Bacillus thuringiensis var. israelensis on benthic macroinvertebrates through direct and indirect exposure. J. N. Amer. Benthological Soc. 13: 190-205.

Alexander, M. K., R. W. Merritt, and M. B. Berg. 1997. New strategies for the control of the parthenogenetic chironomid (Paratanytarsus grimmii) (Diptera: Chironomidae) infesting water systems. J. Amer. Mosq. Contr. Assoc. 13: 189-192.

Lacey, L.A. and R. W. Merritt. 2003. The safety of bacterial microbial agents used for black fly and mosquito control in aquatic environments. In: "Assessment of Environmental Safety of Biological Insecticides" (H. Hokkanen and A. Hajek, eds.). Kluwer Academic Publishers Dordrecht, The Netherlands.

Malmqvist. B., P. Adler, K. Kuusela, R. W. Merritt, and R. S. Wotton. 2004. Black flies in the boreal biome, key organisms in both terrestrial and aquatic environments: A review. Ecoscience 11: 187-200.

Merritt, R. W., J. L. Lessard, K. J. Wessell, O. Hernandez, M. B. Berg, J. R. Wallace, J. A. Novak, J. Ryan, and B. W. Merritt. 2005. Lack of effects of Bacillus sphaericus (Vectolex®) on nontarget organisms in a mosquito control program in southeastern Wisconsin: A 3-year study. J. Amer. Mosq. Contr. Assoc. 21: 201-212.