Effects of Some Pesticides on Spore Germination and Larvicidal Activity of Bacillus thuringiensis var. israelensis and Bacillus sphaericus 2362 Strain


Abstract: The effects of 9 commercial pesticides used commonly in agriculture on spore germination and larvicidal activity of the mosquito pathogenic B. thuringiensis var. israelensis and B. sphaericus 2362 strain were examined. Six of the pesticides was had an inverse impact on spore germination and growth of the test strains. It was determined that the pesticides with the most adverse effect were copper sulfate, methiocarb, and dalapon on spore germination of the microorganisms. Higher concentrations or MIC values of the pesticides reduced the heat-resistant spore numbers of both bioinsecticides, suppressing spore germination. These results indicated that the spores of the bacteria are sensitive to chemical pesticides at the same level. Moreover, the study revealed that the spore germination and larvicidal activity of both biological control agents are affected by pesticides equally. The findings should be considered for assessing the effects of pesticides when both microbial agents are used in field applications.

Keywords: Pesticides, B. thuringiensis var. israelensis, B. sphaericus 2362, Biological control

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