Abstract
The black cutworm, Agrotis ipsilon (Hufn.) (Lepidoptera: Noctuidae) infests many field crops worldwide. Some fractions of natural plant essential oils of terpenes act as contact and stomach poisons against larvae of the pest and also serve as feeding deterrent leading to larval starvation. The tested terpenes (Carvone- Linalol- Nerol- &-terpeniol- Phellandrine and Citronellol) showed different levels in their toxicity against the different stages of A. ipsilon (eggs, larvae and pupae) as they had effects on growth and development. Phellandrine was the most effective terpene against egg and pupal stages, while nerol acted as a stomach or contact poison to 2nd larval instar. The contact treatment of terpenes was more efficient than their stomach toxicity by feeding treatment. Combination of some volatiles and some terpenes increased their efficacy. Oil combinations promoted their effect and decreased insect resistance buildup. The most effective mixture was garlic oil + Nerol. Larvae treated with sublethal concentration (LC50) of terpenes showed some biological differences in their development, deformation in pupae and moths, percentage of sterility increased in the resulting moths, also decreased larval and pupal weight. Combination of Citonellol + garlic oil or mint oil increased their toxicity and decreased the LC50 value. Plant essential oils and terpenes may be used as spray or in bait feeding traps for controlling A. ipsilon as an alternative means of chemical pesticides in IPM programs.