Olfactory response of the zoophytophagous mirid Nesidiocoris tenuis to tomato and alternative host plants

It has been proved that the omnivorouspredator Nesidiocoris tenuis ( Hemiptera: Miridae) is attractedto and can develop successfully on sesame ( Sesamumindicum). In this study, the potential of this plant, compared with Dittrichia viscosaand tomato (Solanum lycopersicum), to attractthe mirid bug was assessed. A Y-tube olfactometerwas used to test the olfactory preference of the mirid in dual-choice bioassays comparing healthy tomato, S. indicum, and D. viscosa plants, and tomato plants infested by eggs and larvae of Tuta absoluta(Lepidoptera: Gelechiidae). To understand the biochemical basis of the attractionof the omnivorouspredator toward the alternative plants, headspace solid-phase microextractioncombined with gas chromatography–mass spectrometry was performed, with the aim of identifying potential volatiles responsible for mirid attraction. S. indicum was the most attractiveplant; T. absoluta infestation did not significantly increase N. tenuis attraction. We identified 57 volatiles belonging to the classes of hydrocarbon and oxygenated monoterpenes, sesquiterpenes, C13- norisoprenoids, aliphatic aldehydes, esters, alcohols, and hydrocarbons. Sesame plants emitted the lowest amount of hydrocarbon monoterpenesbut a higher rate of oxygenated terpenes. Green leaf volatiles, known for attractingmirids, were emitted at higher levels by sesame plants, whereas tomato plants infested by T. absoluta larvae showed the highest levels of monoterpenehydrocarbons. The potential applications of plant volatiles in integrated management of tomato pests are discussed in the framework of mirid ecology.