Identification of plant chemicals attracting and repelling whiteflies

The harmful side effects of chemical pest control have focused increasing attention on the potential for environmentally friendly, sustainable and efficient methods to control the sweet potato whitefly, Bemisia tabaci (Gennadius). One control method employs a volatile repellent (push), and an alluring volatile trap (pull) to manipulate the distribution and control the whitefly. Here, a Y-tube olfactometer was used to investigate the orientation responses of the whitefly toward the volatile components of six plants: tomato, tobacco, cabbage, cotton, cucumber and celery. Gas chromatography coupled with mass spectrometry was used to identify and quantify extracts from the six plants. Six treatments were conducted to demonstrate the “push–pull” method’s effects on the host selection behaviors of B. tabaci in a greenhouse. Four of the plant extracts tested had exceedingly attractive effects on the adult insects, but not those from celery. B. tabaci exhibited a prominent attraction response to (E)-2-hexenal, 3-hexen-1-ol and mixtures of these compounds, with the response rates exceeding 80 % for all tested proportions. Limonene diluted 500 times had a 62 % greater deterrent effect on adults than was observed in its absence, and it repelled egg-laying by more than 80 % in the greenhouse experiment. These data show that (E)-2-hexenal, 3-hexen-1-ol and limonene can be expected to be used for the “push–pull” method to control B. tabaci.