Electrophysiological and behavioural responses of Plutella xylostella L. (Lepidoptera: Plutellidae) to thirteen non-host plant essential oils

The diamondback moth (DBM), Plutella xylostella (L.), is a cosmopolitan obligate pest of cruciferous crops. Currently, DBMs management is largely dependent on broad-spectrum synthetic pesticides, which has led to the adverse effects on the environment, human health, and nontargeted organisms. Thus, alternative control methods are needed. The essential oils (EOs) derived from bioactive species may be developed as effective alternatives for the management of DBMs that is safe and eco-sustainable than conventional pesticides. In this study, we investigated electrophysiological (EAG) and behavioral responses of DBM adults to the thirteen nonhost EOs of Acorus calamus, Ageratum conyzoides, Artemisia argyi, Chenopodium ambrosioides, Cymbopogon citratus, Foeniculum vulgare, Ocimum basilicum, Pelargonium hortorum, Perilla frutescens, Pogostemon cablin, Polygonum hydropiper, Rosmarinus officinalis, and Ruta graveolens in order to contribute to the development of low environmental impact management alternatives. EAG recordings revealed all the tested EOs significantly elicited EAG responses of DBM females, and the males were sensitive to the eleven EOs except A. conyzoides and O. basilicum. Meanwhile, EAG recordings of DBMs exhibited dose-dependent responses to these tested EOs in most cases. In Y-tube olfactometer bioassays, the EOs of A. calamus, C. citratus, P. hortorum, P. hydropiper, and R. graveolen demonstrated prominent repellent effects on DBM females at concentrations of 10 mu g/mu L or higher. The results of oviposition bioassays found the number of eggs on the two plants with the five tested EOs were less than that on the two plants with paraffin oil. And the oviposition indexes of the plants that fixed with the EOs of P. hortorum, R. graveolen, A. calamus, P. hydropiper, C. citratus, and paraffin oil were -71.81%, -59.43%, -57.46%, -51.11%, -35.41%, and 0.09%, respectively. These findings indicate that the five EOs, especially P. hydropiper EO, provide active and safe tools for natural repellents to prevent and control DBMs infestations of cruciferous vegetables.