Efficacy of flowable concentrate formulations of Bacillus thuringiensis var. israelensis against black flies (Diptera:Simuliidae).

Seven flowable concentrate formulations of Bacillus thuringiensis (H-14), Teknar wdc, auto-dispersible Teknar, Teknar 2X aqueous concentrate, Teknar 2X oil base concentrate, Vectobac AS, Bactimos FC and Skeetal F, were evaluated in small streams against Simulium vittatum. There was no significant difference in efficacy among the formulations with the exception of the Teknar 2X aqueous concentrate, which required considerably less formulation (5 mg/liter/1 min) than the others to produce 95% mortality in penultimate instars of S. vittatum. The field determined LC-95 for the other formulations ranged from 10.6 to 15.9 mg/liter/1 min. There was no significant difference between the efficacy of excessively diluted and undiluted formulations.