Attraction of wireworms to root-emitted volatile organic compounds of barley

Wireworms, the belowground larvae of click beetles (Coleoptera: Elateridae), represent a threat for various crops, including cereals, potatoes and small fruits, in many countries. In order to promote the development of bio-pesticides or the selection of resistant varieties, studies concerning the close relationship between wireworms and the roots they attack have to be conducted. Indeed, lacks of knowledge in the chemical ecology of these small but consequent pests baffle such achievements. Here, we studied the reactions of wireworms (Agriotes sordidus Illiger) facing root-emitted volatile organic compounds (VOCs) of barley.
We first tested the ability of wireworms to orientate towards a blend of volatile compounds emitted by seven day’s old mashed roots of barley grown in vermiculite. We used a Y-shaped horizontal olfactometre, which inferior half was filled with compressed and humidified vermiculite. Wireworms were able to detect blends of volatiles emitted by mashed roots, and to orientate their foraging behaviour toward the emission source. Volatile compounds were identified from barley roots using SPME-GC-MS and several chemicals were identified.
This study is part of a larger programme which purpose is the identification of VOCs emitted by the roots of barley and different actors of the rhizosphere, and to assess their semiochemical functions.