Plagiodera versicolora (Laicharting, 1781) (Coleoptera: Chrysomelidae) is an important forest pest which damages many trees such as willow, poplar, and hazelnut. In order to find new microbes that can be utilized as a possible microbial control agent against this pest, we investigated the culturable bacterial flora of it and tested the isolated bacteria against P. versicolora larvae and adults. We were able to isolate nine bacteria from larvae and adults. The isolates were characterized using a combination of morphological, biochemical, and physiological methods. Additionally, we sequenced the partial sequence of the 16S rRNA gene to verify conventional identification results. Based on characterization studies, the isolates were identified as Staphylococcus sp. Pv1, Rahnella sp. Pv2, Rahnella sp. Pv3, Rahnella sp. Pv4, Rahnella sp. Pv5, Pantoea agglomerans Pv6, Staphylococcus sp. Pv7, Micrococcus luteus Pv8, and Rahnella sp. Pv9. The highest insecticidal activity against larvae and adults was obtained from M. luteus Pv8 with 50 and 40 % mortalities within 10 days after treatment, respectively. Extracellular enzyme activity of the bacterial isolates such as amylase, proteinase, lipase, cellulose, and chitinase was also determined. Consequently, our results show that M. luteus Pv8 might be a good candidate as a possible microbial control agent against P. versicolora and were discussed with respect to biocontrol potential of the bacterial isolates.

Symbiotic bacteria associated with insects play important roles in different physiological processes such as digestion, insect behavior, defense and providing essential nutrition in insect gut. In addition, these bacteria can be used in biocontrol of insect pests using genetic engineering techniques. The first step is to isolate and identify symbiotic bacteria from insects to elucidate their roles, and to use in the development of transgenic strains. For this purpose, we isolated and characterized the bacterial isolates from stored product pests using a combination of conventional tests and 16S rRNA sequence analysis. The bacterial flora of Callosobruchus maculatus included Bacillus pumilus, Staphylococcus sp. and Pantoea sp. Acanthoscelides obtectus flora included Staphylococcus kloosii, Staphylococcus sp., S. saprophyticus and Enterococcus faecalis. The internal flora of Sitotroga cerealella included Staphylococcus succinus, Enterococcus sp. and Staphylococcus sp. Finally, Phthorimaea operculella flora included Bacillus sp., S t a p h y l o c o c c u s s c i u r i , E n t e ro c o c c u s m u n d t i i , E. casseliflavus, Alcaligenes faecalis, Enterobacter sp., Pantoea agglomerans and Pseudomonas fluorescens.

Entomopathogenic microorganisms such as bacteria, fungi, viruses, nematodes and protozoa play an important role for regulation of insect pest populations and, this leads to use these microorganisms as biological control agents against pest species as an alternative to chemicals insecticides. In this study, we tested different bacteria originated from stored product pests and fungi isolated from different sources against two important stored product pests, Acanthoscelides obtectus (Say) (Coleoptera: Chrysomelidae) and Callosobruchus maculatus (F) (Coleoptera: Bruchidae), under laboratory conditions. Based on the laboratory screening, the highest mortality against A. obtectus within bacteria and fungi was obtained from Staphylococcus kloosii Fbe-10 with 73% and Lecanicillium muscarium ARSEF3600, Beauveria pseudobassiana ARSEF8664 and, Beauveria bassiana ARSEF8668 with 100%, respectively. Also, the highest mycosis within fungi was obtained from Lecanicillium muscarium ARSEF3600 and Beauveria bassiana ARSEF8668 with 100%. The highest mortality against C. maculatus within bacteria and fungi was obtained from Bacillus pumilus Be-2with 57% and Lecanicillium muscarium ARSEF3600, Beauveria pseudobassiana ARSEF8664 and, Beauveria bassiana ARSEF8668 with 100%, respectively. Also, the highest mycosis within fungi was obtained from Beauveria bassiana ARSEF8668 with 90%. These results showed that the fungal isolates used in this study seem to be more effective than bacteria and, should be further investigated in terms of developing microbial control agent against stored product pests.