Plant-derived attractants and repellents for the economically important pest Otiorhynchus pseudonothus (Coleoptera: Curculionidae): differences between the sexes

The weevil Otiorhynchus pseudonothus Apfelbeck, 1897 (Coleoptera, Curculionidae) is polyphagous pest damaging various species of ornamental and horticultural plants. The weevils damage both the underground and the above-ground parts of the plant: larvae feed on roots meanwhile adults on leaves. The aim of our study was to identify plant-origin attractants and repellents for O. pseudonothus species that could be applied in the integrated pest management. For this purpose, chemo-ecological studies on the insect pests were needed and conducted. GC-EAD analysis of the headspace samples from undamaged and O. pseudonothus adult-damaged common lilac (Syringa vulgaris L.) leaves revealed the presence of 5 alcohols and 3 aldehydes eliciting antennal responses in both male and female. Behavioral assays using a Y-olfactometer indicated sex-specific responses: hexan-1-ol, (E)-2-hexen-1-ol, and benzyl alcohol were significantly attractive to males but not to females, whereas females showed a significant preference for (E)-3-hexen-1-ol only. The responses of O. pseudonothus males and females to the mixtures of attractive compounds also remained sex-specific. Only one single compound, (Z)-3-hexen-1-ol, was repellent to males, and none of the EAD-active single compounds showed repellency to females. This study provides the first identification of compounds that are attractive or repellent to the economically important pest O. pseudonothus, offering new opportunities for their use in integrated pest management strategies.