Study on the feasibility of buckwheat as a trap plant for flower thrips (Frankliniella intonsa) in sunflower field

Frankliniella intonsa (Thysanoptera: Thripidae) is a significant invasive pest that can damage numerous plants and crops and spread the tomato spotted wilt virus. During the sunflower flowering period in the primary sunflower production area in China, F. intonsa-infested sunflower heads produce kernels with marked visual damage, including peel scratches, which reduce seed quality and profitability. In this study, the behavioral responses of F. intonsa to buckwheat and sunflowers were measured in a Y-tube. Meanwhile, gas chromatography-mass spectrometry was performed to determine the volatile components of inflorescences of both sunflower and buckwheat and the behavioral effects of these components were evaluated on F. intonsa in a Y-tube. The results revealed that sunflower leaves significantly repelled adults and nymphs of F. intonsa both in olfactometer bioassays. However, F. intonsa was significantly attracted by the volatiles from the leaves and flowers of buckwheat. Interestingly, F. intonsa adults preferred sunflower flowers over buckwheat flowers. Among the four kinds of sunflower flower volatiles selected, F. intonsa was attracted by two kinds of volatiles (gamma-terpinene and (R)-( +)-limonene), while one volatile (beta-pinene) had the effect of repelling F. intonsa, while among the four selected buckwheat flower volatiles, F. intonsa were attracted by three kinds of volatiles (alpha-caryophyllene, verbenone, octane). Finally, the field-trapping effect of buckwheat on F. intonsa was verified by a sunflower-buckwheat intercropping experiment. The results of this study provide a theoretical basis for the feasibility of intercropping with buckwheat and sunflower to control F. intonsa. Thus, buckwheat can be used as a trapping plant in fields to prevent F. intonsa invasion.