Behavioral response of the greenhouse whitefly (Trialeurodes vaporariorum) to plant volatiles ofOcimum basilicumandTagetes minuta

The use of chemical pesticides as a main pest control strategy has been highly criticised due to environmental pollution and negative effects on natural enemies of pests. In modern farming, it is essential to implement integrated pest management approaches that seek to control insect pests without causing environmental damage, e.g. the use of companion plants. Basil and Mexican marigold are often used as companion plants to attract greenhouse whiteflies, hence reducing damage to solanaceous crops, but the mechanism and role of volatile cues in crop protection strategies are unknown. This study found that both flowering basil and marigold were preferred to tomato by the greenhouse whitefly (Trialeurodes vaporariorum) in Y-tube olfactometer bioassays. PCA revealed that some volatiles were more correlated to one stage than to another. The dominant volatile constituents of Mexican marigold are limonene, dihydrotagetone, (Z)-beta-ocimene, alpha-pinene, (Z)-3-hexenyl acetate, and those from basil are linalool, 1,8-cineole, eugenol and beta-elemene. Among these dominant compounds, 1,8-cineole and (Z)-3-hexenyl acetate elicited strong attraction in greenhouse whitefly at 0.01%, whereas (Z)-beta-ocimene and linalool elicited strong repellence at 0.1% and 1% dosages. This suggested that the basil flowering stage attraction is due to 1,8-cineole. These volatiles demonstrated potential as lures or bio-repellents and could be used in a push-pull semiochemical approach for greenhouse whitefly management.

Automated summary

The study found that the volatile compounds from basil and Mexican marigold can attract greenhouse whiteflies, potentially serving as lures or bio-repellents for pest management. This suggests that the use of these volatiles could be effective in a push-pull semiochemical approach for controlling greenhouse whiteflies.