Özet:

Agrotis segetum (Denis & Schiffermüller) (Lepidoptera: Noctuidae) is one of the most serious pests in Iran that attacks nearly all vegetables. Using synthetic insecticides is the main controlling method of this pest. Human and environmental health hazards on insecticides usage encourage scientists to search for alternative safer methods. This research is devised to evaluate the potential of two indigenous entomopathogenic nematodes against this pest. Ability of different concentrations of infective juveniles to infect penultimate and last instars larvae, pre-pupa and pupa was assessed under laboratory condition after 12, 24 and 48 h. Susceptibility of larval stages, pre-pupa and pupa to different concentrations of both entomopathogenic nematodes was evaluated in a pot experiment. Final instar larvae was the most susceptible stage in both laboratory and greenhouse condition. Pre-pupa was more vulnerable to entomopathogenic nematodes as compared with pupa. The mortality increased with increasing in the time of exposure. After 12 hours, the LD50 of Heterorhabditis bacteriophora (Poinar) and Steinernema carpocapsae (weiser) on final instar larvae were 34 and 56 infective juveniles per 10 cm Petri dish respectively. About 98 and 90% of final instar larvae were parasitized five days after exposing to H. bacteriophora and S. carpocapsae in the greenhouse. According to the results, these two indigenous entomopathogenic nematodes have good potentials in managing A. segetum.

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