Volatiles from essential oils of three Lamiaceae plants repel the winged cotton aphid, disturb its feeding behavior and reduce its fecundity.

Abstract

Insects use odor detection to sense their surroundings. Use of volatile compounds, such as essential oils (EOs) of plants, to repel pests and disrupt their olfaction-driven behaviors has great practical potential for use in integrated pest management. Despite the available information on the repellent effects of EOs on herbivorous insects, the olfaction-based mechanisms remain unknown. Y-tube olfactometer tests showed that the EOs of three Lamiaceae plants - Mentha arvensis L., Mentha piperita L. and Lavandula angustifolia Mill. - were significantly repellent to winged cotton aphid, Aphis gossypii Glover. Electropenetrography (EPG) tests indicated the EOs reduced phloem feeding and increased the level of nonproductive probing by the aphids. The EOs also reduced the fecundity of winged A. gossypii. Electrophysiological bioassays and mass spectrometry (GC-MS) identified five physiologically active volatiles, i.e., menthone, isomenthone, neomenthol and menthol from M. piperita; menthone and menthol from M. arvensis; and linalool from L. angustifolia. Behavioral tests confirmed that all five compounds repelled winged A. gossypii. Under field conditions, the growth rate of aphid populations after seven days was significantly lower in fields treated with these compounds than in the control fields. Our findings demonstrated that three EOs not only repelled winged A. gossypii but also interfered with the aphid's feeding behavior and reduced its fecundity. These EOs and their active constituents have great potential as eco-friendly control products for use against A. gossypii. The effects of these EOs also exceed other repellents that only keep pests away from host plants. This article is protected by copyright. All rights reserved.