ARABLE: Field evaluation of synthetic blends of semiochemicals for monitoring and control of wireworms

Soil-borne pests are a major limiting constraint in crop production. Agriotes spp. wireworms (Coleoptera: Elateridae) are major soil-dwelling pests of cereal and root vegetable crops in Europe and North America, with A. lineatus, A. obscurus and A. sputator causing significant annual crop yield losses (10-100%) in the UK alone through larval feeding behaviour. Management of Agriotes spp. currently involves deployment of pheromones to monitor adult populations, and use of seed treatments and organophosphate insecticides to protect crops from larval feeding damage. However, current chemical options are challenged in Europe, and uncertainty remains if at all new soil insecticides could be registered for wireworm management in the near future. Furthermore, predicting the extent of subsequent larval damage from pheromone trap catch is problematic and has its shortfalls. To address the problem with management of wireworms at the feeding stage, we are investigating the use of rhizosphere-derived volatile organic compounds (rVOCs) as novel, environmentally benign biopesticides for larval management. Similar to aboveground insects, soil-dwelling insects are also attracted to or repelled by semiochemicals (behaviour-modifying chemical signals) that occur in the gas phase and diffuse in soil pores. Whilst carbon dioxide is a generic attractant, rVOCs provide more specific, mid-range host location cues for soil pests. Our lab has recently isolated and identified rVOCs which attract wireworms in soil olfactometer (behaviour) assays. We will test rVOC synthetic blends against wireworms in proof-of-concept field experiments using slow-release prototype formulations. The proposed study is an important step in the development of attract-and-kill strategies for wireworm management, which could also be extended to the management of other soil-dwelling pests.