An investigation on insecticidal effects of three growth stimulant bacteria belong to Pseudomonas sp. to control Anagasta kuehniella and the infected larvae on the host selecting by the parasitoid wasp, Habrabracon hebetor

The Pseudomonas bacteria include many species with different characteristics. Some species of the genus are considered as the plant growth stimulants. Recently, the potentials of the bacteria to insect pest control has been documented. In this study, the lethal effects of three strains, Pseudomonas protegens CHA0, P. soli VF16, and P. persica VKh13 to eggs and larvae of Anagasta keuhniella (Zeller) (Lep., Pyralidae) as an important stored product pest was studied. For this purpose, two concentrations of each strain, 0.2 and 0.5 OD at the wavelength of light of 600 nm, were provided and the 5th instar larvae and eggs of A. keuhniella were treated and the mortalities were recorded after 24h. Statistical investigations indicated that the strain P. protogens CHA has the highest mortality rate (79.16%) and after that, the strain P. soli VF16 (64.15%). Furthermore, it is demonstrated that the strain P. persica VKh13 has not the insecticidal property. The bacterial efficacy at suspension concentration 0.5 OD was significantly more than 0.2 OD. No significant difference was observed between susceptibility of the pest larva and eggs to different investigated strains in the study. The highest mortality was observed in application of the concentration 0.5 OD of P. protogens CHA on the pest larvae. Olfactory trials indicated that the female parasitoid wasps, Habrabracon hebetor, significantly avoided from treated larvae by all of the three strains. The results can be used for developing the microbial control of the pest.