The effect of entomopathogenic nematode, Steinernema carpocapsae (Weiser) on mortality of the last instar larvae and pupae of Plodia interpunctella (Huebner) under laboratory conditions

A number of soil samples were collected from different districts of Kohgiluyeh and Boyer Ahmad province to study the entomopathogenic nematodes in 2010. Steinernema carpocapsae (Weiser) was isolated from the collected soil. Due to limitations of chemical pesticides uses against storage pests, a study performed to determine the effectiveness of the isolated entomopathogenic nematode on Indian moth, Plodia interpunctella (Huebner), a major pest of stored products. In this experiment, larval and pupal stages of Indian moth were exposed to concentrations of 0, 250, 500, 1000 and 2000 infective juvenile/ml of distilled water at 27˚C. Insects were placed on filter paper impregnated with 1 ml of nematode suspension in Petri dishes (9 cm in diameter) for 2 days. Number of dead insects was counted every 24 hrs. The highest mortality was recorded after 48 hrs which was 99% pupal stage at the concentration 1000 IJs, whereas it was 2000 IJs for the larval stage which caused a total mortality of the tested insect. In this study, pupal stage was more sensitive than larval stage to lower concentration of entomopathogenic nematodes.