Isolation and insecticidal activity of some bacteria from the hazelnut beetle (Balaninus nucum L.)

The hazelnut beetle (Balaninus nucum L., Coleoptera: Curculionidae) is the single greatest source of damage to hazelnut fruits throughout the world. I t causes approximately 30-40% of the total economic damage to hazelnut prod ucts per year in Turkey. In this study, we investigated the bacterial flora of the hazelnut beetle collected from the vicinity of Trabzon (Turkey) dur ing 1995-1997 and tested them for insecticidal activities. The number of to tal bacteria in larvae (1.8 x 10(9) cell/larva) and adults (1.41 x 10(11) c ell/adult) was identified. Based on colony colour and morphology, five isol ates were identified. According to morphological, physiological, biochemica l and molecular characters of the isolates, they were identified as Bacillu s thuringiensis, Pseudomonas fluorescens, Micrococcus luteus, Serratia marc escens and Escherichia coli. The insecticidal activities of these bacterial isolates on third-stadium larvae of B. nucum were investigated. The highes t insecticidal effect determined on B. nucum within three days was 100% wit h S, marcescens. The effects of the rest of the isolates are 45% for B. thu ringiensis, 20% for P. fluorescens, 30% for M. luteus and 25% for E. coli.