Investigation of culturable bacterial flora and microbial agent of Ostrinia nubilalis (Lepidoptera: Pyralidae)

Corn borer (Ostrinia nubilalis Hbn. Lepidoptera: Pyralidae) is a polyphage pest and widespread in all over the world specially in Turkey. Ostrinia nubilalis larvae cause a serious damage to maize as well as millet, hemp, hop, and it is capable of injuring peppers, sorghum, cowpea, soy-bean, fruit of beans and cotton. Studying the bacterial flora of the pests are important for both determining a significant bio-control agent and insect resistance. For this purpose, Ostrinia nubilalis larvae were collected from various fields of Eastern Black Sea region of Turkey. Total of 26 different cultured bacteria were isolated from these larvae and identified as Pseudomonas aeruginosa (On1), Brevundimonas aurantiaca (On2), Chryseobacterium formosense (On3), Acinetobacter sp. (On4), Microbacterium thalassium (On5), Bacillus megaterium (On6), Serratia sp. (On7), Ochrobactrum sp. (On8), Variovorax paradoxus (On9), Corynebacterium glutamicum (On10), Serratia sp.(On11), Paenibacillus sp.(On12), Microbacterium sp.(On13), Alcaligenes faecalis (On14), Microbacterium testaceum (On15), Enterococcus sp. (On16), Enterococcus sp. (On17), Leucobacter sp. (On18), Paenibacillus sp. (On19), Alcaligenes faecalis (On20), Microbacterium thalassium (On21), Microbacterium sp. (On22), Leucobacter sp. (On23), Alcaligenes faecalis (On24), Serratia sp. (On25), Serratia marcescens (On26). Our results indicate that isolates coded as On13, On16, On19 and On22 are probably novel isolates. The highest insecticidal effect was 100% by On1 (Pseudomonas aeruginosa) and On16 (Enterococcus sp.) againts the 3th instar pest larvae within fourteen days. Also, the highest insecticidal effects of Bacillus isolates isolated from different pest species was performed on Ostrinia nubilalis. The highest insecticidal effect was 80% by Xd 3(Bacillus thuringiensis) againts pest larvae within fourteen days. Consequently, On1 and On16 appear to be the most promising bio-control agents against Ostrinia nubilalis.