Bioactivity of essential oils from three species of Mentha against Plutella xylostella (Lepidoptera: Plutellidae)

Botanical derivatives constitute an important option for the reduction in the use of synthetic insecticides for the management of agricultural pests. The larval form of the diamond back moth, Plutella xylostella , is one of the main pests of the family Brassica and is resistant to synthetic insecticides. The aim of the present study was to test the potential of commercially available essential oils (EOs) from the genus Mentha on P. xylostella . EOs from M. arvensis , M. spicata and M. piperita were investigated. Topical toxicity and residual contact toxicity tests were conducted, along with the assessment of biological parameters, feeding deterrence and repellency. Phytotoxicity to Brassica leaves was also investigated. The oil from M. piperita was the most toxic to P. xylostella by topical contact, whereas the oil from M. spicata was the most toxic by residual contact. Overall, the Mentha oils were more toxic by topical contact than residual contact. The EOs from M. arvensis and M. spicata significantly altered the weight of the pupae and larval survival. All Mentha oils tested caused feeding deterrence in P. xylostella . The EO from M. piperita exhibited persistent repellence over time compared to the other EOs. The oils administered at the maximum doses tested did not cause phytotoxicity to Brassica leaves. The present results demonstrate the potential of essential oils from plants of the genus Mentha , altering biological and behavioral aspects of P. xylostella .