Bioactivity of Essential Oils from Three Species of Mentha L. Against Plutella Xylostella (Linnaeus, 1767) (Lepidoptera: Plutellidae).

Abstract

Botanical derivatives constitute an alternative for reduction in the use of synthetic insecticides in the management of agricultural pests. The larval form of the diamond back moth, Plutella xylostella, is one of the main pests of the family Brassicaceae and is resistant to synthetic insecticides. The insecticidal potential of Mentha L. essential oils (EOs) on P. xylostella has been investigated. The aim of the present study was to test the potential of commercially available EOs from the genus Mentha L. on P. xylostella. EOs from Mentha arvensis L., Mentha piperita L., and Mentha spicata L. 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 oleracea L. 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. Mentha EOs administered at doses corresponding to the LC₉₅ estimated in the concentration-response curve were tested and did not cause phytotoxicity to Brassica oleracea L. leaves. The present results demonstrate the potential insecticide of OEs commercial of Mentha in the management of the P. xylostella, causing topical and residual mortality, altering biological and behavioral aspects, and can be used as an alternative to conventional chemical control.