Entomopathogenic activities of environmental isolates of Bacillus thuringiensis against dipteran larvae
Lonc, E.; Doroszkiewicz, W.; Klowden, M.J.; Rydzanicz, K.; Galgan, A.
Journal of Vector Ecology Journal of the Society for Vector Ecology 26(1): 15-20
2001
ISSN/ISBN: 1081-1710 PMID: 11469180 Document Number: 536500
Twenty-five isolates of Bacillus thuringiensis from the Lower Silesia region of Poland, the Osola plain, and phylloplane niches and soil samples from the Karkonosze National Park were tested for insecticidal activity against larvae of the dipterans Aedes aegypti, Drosophila melanogaster and Musca domestica. The spore-crystal mixture of B. thuringiensis finitimus (soil isolate) killed nearly half of the 4th instar larvae of A. aegypti. A similar mortality rate between 39-61% was recorded after treatment with two phylloplane isolates belonging to biochemical type I of B. thuringiensis (subsp. japonensis, yoso and jinghongiensis) and type IV (subsp. tochigiensis,). The effect of B. thuringiensis wratislaviensis H-47 was lowest, with larval mortality ranging from 7-28%. The susceptibility of D. melanogaster, evaluated as percentage of larvae that did not survive to adulthood, varied between 0-38% and 0-45% at dosages of 0.5 and one ml, respectively. The LC50s ranged from 5.07 x 109 to 1.04 x 1011 spore-crystal mixture. The LC50s for M. domestica larvae were 4.1 to 4.8 x 108 spores/ml of B. thuringiensis finitimus and the phylloplane strain KpC1 (I type) and 2.9 x 109 for the phylloplane representative of group I. Generally, all tested isolates showed the most activity against common fly larvae. The highest (64-81% mortality) was observed after treatment with both phylloplane (OpPs1, KpF3, KpC1) and soil isolates (KsAc1) of biochemical type I as well as B. thuringiensis finitimus (type III).