Abstract
Plant-derived volatile organic compounds (VOCs) are widely used as insect attractants for population monitoring, offering an efficient and eco-friendly approach to pest management. Since thrips are the dominant pest species in alfalfa (Medicago sativa) crops, alfalfa volatiles produced in the presence of Odontothrips loti and compounds with attractive potential to both O. loti and Frankliniella occidentalis were investigated. Using gas chromatography-mass spectrometry (GC-MS), 96 VOCs were identified from seven alfalfa cultivars with varying levels of thrips resistance with and without damage by O. loti. Eleven volatiles were selected for Y-tube olfactometer assays. The semiochemical p-Menth-8-en-2-one, which was suppressed in alfalfa subject O. loti damage, significantly attracted both O. loti and F. occidentalis in Y-olfactometer bioassays; the response rates were 2.05~3.07 times compared to control (p < 0.05). Further experiments confirmed p-Menth-8-en-2-one, dispensed through PE (Polyethylene) vials, was the most effective lure material with the concentrations of 10 ng/μL. This study demonstrated that the alfalfa-derived volatile p-Menth-8-en-2-one, shows significant attraction to thrips, which can be utilized for monitoring and management of odontothrips loti and frankliniella occidentalis.