Isolation and identification of Bacillus pumilus YHH-2, a potential pathogen to the alfalfa weevil (Hypera postica Gyllenhal)

Alfalfa weevil (Hypera postica Gyllenhal, 1813) samples were collected from different locations in Kirsehir, Turkey, during May-August in 2014. They were immediately transferred to the research laboratory and dissected under aseptic conditions. Then serial dilutions were prepared from digestive tract samples and the spread plate technique was used for obtaining pure cultures. The conventional and molecular methods that include morphological and physiological examinations, biochemical tests, 16S rDNA sequencing, and the basic local alignment search tool (BLAST) were used for identification of the bacterial isolates. According to the findings of the present study, the YHH-2 isolate was found as the main pathogenic bacterium that dominates the digestive tract microflora of the alfalfa weevil. 16S rDNA sequencing and the BLAST data revealed that YHH-2 showed 100% similarity to Bacillus pumilus, recently described as an entomopathogenic strain. In conclusion, the results of the present study are important due to showing for the first time the presence of Bacillus pumilus Y HH-2 in the digestive tract of the alfalfa weevil and it may be used as a potential biocontrol agent against the harmful effects of this insect species.