Dual action of Catsia tora in tea plantations: repellent volatiles and augmented natural enemy population provide control of tea green leafhopper

Abstract

The tea green leafhopper Empoasca vitis Gothe (Homoptera: Cicadellidae) has become the key insect pest affecting tea plantations in southern China. The control of E. vitis with chemical insecticides is not only costly but also has serious undesirable effects. It is therefore imperative that environmentally sound and sustainable management alternatives be developed. The aim of this study was to evaluate the potential of using the non-host plant Catsia tora (Fabaceae) as a cover crop for the control of E. vitis in tea plantations. The volatile organic compounds derived from the C. tora plants were shown to be repellent to leafhoppers. These compounds were collected through headspace absorption, and its 19 components were identified through gas chromatography–mass spectrometry. Based on the behavioral responses of E. vitis to 11 of these volatile compounds (those with relative amounts greater than 1), three bioactive compounds (p-cymene, limonene, and 1,8-cineole) were observed to play a key role in the regulation of the E. vitis population and were significantly effective at repelling leafhoppers. The intercropping of C. tora in a tea field markedly reduced the E. vitis population levels and promoted an increase in the natural enemies of this pest, such as spiders, coccinellids, and lacewings. Our findings suggest that the sustainable pest management achieved using C. tora as a cover crop offers an interesting alternative strategy for the control of this important tea pest.