Synergistic effect between Bacillus thuringiensis Berliner and Metarhizium anisopliae (Metschnikoff) Sorokin against Chrysomya albiceps larvae (Wiedemann, 1819)(Diptera: Calliphoridae) under laboratory conditions

Abstract

Commercial microbial pesticide based on bacterial pathogen Bacillus thuringiensis israelensis B.t.i. (Antrol) and fungus pathogen Metarhizium anisopliae, were applied alone and in combinations against larvae of blow fly Chrysomya albiceps under laboratory conditions.The study showed that using two concentrations of B. thuringiensis israelensis (100 and 200 ppm) and M. anisopliae 2.8×106 and 2.8×107 conidia/ml) by mixing the food of second instar larvae of Ch. albiceps and direct spraying the larvae with fungal suspension led to high and rapid mortalities more than using the pathogen alone. The accumulated mortalities when treating the combination B (2.8×106 conidia/ml +200 ppm) of M. anisopliae and B.t.i. respectively and direct spraying with fungus suspension was 86.67%, while those mortalities when using the bacterial suspension and fungal suspension alone was 56.67% and 16.67% respectively.Results also showed that mortality percent increases with time e.g. it was 36.67% after 24 hr. of the treatment with B combination increased to 84.67% after 12 days. While the treatment with the bacterial suspension caused 10% mortality after 24 hr increased to be 54.44% after 12 days, while using fungal suspension alone did not cause any mortality after 24 hr but after 12 days mortality increased up to 13.70% only. These results indicated that using a combination of two pathogens has a synergistic effect.