Laboratory and field investigation on the orientation of Frankliniella occidentalis (Thysanoptera: Thripidae) to more suitable host plants driven by volatiles and component analysis of volatiles.

Abstract

Differences in population densities of Frankliniella occidentalis among different plant species suggest a preference for particular hosts. Host plant volatiles are often involved in insect fitness. However, few studies have explored the interaction between flower volatiles and fitness. The host fitness of F. occidentalis for different flowers was assessed through field investigation, and the olfactory preference of thrips for flower volatiles was tested in the laboratory. In the field study, 18 flower host plants were classified at four fitness levels by F. occidentalis. Olfactory tests showed that female F. occidentalis had significantly different preferences for different plant odours among the volatiles of the four tested flowers (each representing the four fitness levels), whereas male F. occidentalis did not. The relative response of F. occidentalis females to flower volatiles (Rosa rugosa > Dianthus caryophyllus > Gerbera jamesonii > Pelargonium hortorum) was consistent with the field performance of F. occidentalis. In total, 23, 29, 16 and 26 components were identified in the volatile profiles of R. rugosa, D. caryophyllus, G. jamesonii and P. hortorum, respectively. 3,5-Dimethoxytoluene (24.94%), nonanal (30.42%), (E)-3-penten-2-one (52.31%) and zingiberene (29.88%) were the single most abundant components of the volatiles of R. rugosa, D. caryophyllus, G. jamesonii and P. hortorum, respectively. Volatiles are important in attracting F. occidentalis to suitable hosts, and differences in the types and concentrations of volatile components among flowers may directly influence the olfactory responses and field performance of thrips. Potential attractants could be developed for integrated pest management programmes against this pest. © 2018 Society of Chemical Industry.