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Laboratory Evaluation of Commercial Formulations of Bacillus thuringiensis var. israelensis Against Mosquito and Black Fly Larvae.

TitleLaboratory Evaluation of Commercial Formulations of Bacillus thuringiensis var. israelensis Against Mosquito and Black Fly Larvae.
Publication TypeJournal Article
Year of Publication1984
AuthorsMolloy, DP, Wraight, SP, Kaplan, B, Gerardi, J, Petersen, P
JournalJournal of Agricultural Entomology
Volume1
Pagination161-168
Keywordsbiology
Abstract

Three   commercial  black   fly  and  mosquito   larvicidal   formulations   of  Bacillus

thuringiensis Berliner var. israelensis de Barjac were bioassayed to determine their potencies relative to the international standard powder, IPS-78. The potencies of the wettable powder (WP) formulations of Bactimos™ and Vectobac™ and the water dispersible concentrate (WDC) TeknarN were determined to be 4530, 5723, and  336 International Toxic Units (ITU)/mg, respectively, against Simulium spp.; their respective ITU/mg values against Aedes aegypti (Linnaeus) were 3556, 2317, and 1373. Little correlation (r2 = 0.47) was evident between the potency rating (ITU/mg) of the formulations against mosquitoes and black flies; this indicated that the potency rating of a formulation against black flies cannot be simply predicted from the A. aegypti ITU/mg rating on its label. A moderate correlation between formulation potency and mean particle size was observed in the black fly assays (r2 = 0.77), but not against mosquitoes (r2 = 0.20). Aqueou s suspensions of Teknar-WDC had a significantly smaller mean particle size and stayed significantly longer in suspension than other formulations. The relatively long duration of suspension of Teknar-WDC was viewed as important since the toxic crystals wou ld be less likely to settle out in mosquito and black fly habitats. A ratio based on the LC50 values determined from standardized bioassay methods is suggested as a convenient way to express the relative  potency of a formulation against mosquitoes and black flies.

 

URLhttp://scentsoc.org/Volumes/JAE/v1/2/00012161.pdf