02336nas a2200181 4500008004100000245013500041210006900176300001200245490000600257520173800263653001202001100001902013700002002032700001502052700001602067700001702083856005402100 1984 eng d00aLaboratory Evaluation of Commercial Formulations of Bacillus thuringiensis var. israelensis Against Mosquito and Black Fly Larvae.0 aLaboratory Evaluation of Commercial Formulations of Bacillus thu a161-1680 v13 a

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.

 

10abiology1 aMolloy, D., P.1 aWraight, S., P.1 aKaplan, B.1 aGerardi, J.1 aPetersen, P. uhttp://scentsoc.org/Volumes/JAE/v1/2/00012161.pdf