Discovery and Field Evaluation of Sex Pheromone Components for the Click Beetle Melanotus verberans (LeConte) (Coleoptera: Elateridae).

Abstract

Wireworms, the larval stage of elaterid beetles, are among the most serious soil-borne insect pests in the world. Wireworms feed on a variety of key crops, including small grains, maize, vegetables, fruits, sugar cane, sugar beets, potatoes, and sweet potatoes. Management of these pests is becoming increasingly problematic, in part due to knowledge gaps in their basic biology, which hinders development of effective crop protection strategies. In particular, little is known about the semiochemicals that mediate the reproductive behavior of these pests. Research over the past two decades has begun to fill this need, with: (1) the discovery of sex attractants for several key pest species, and (2) subsequent studies toward development of semiochemically-based pest management approaches. We used chemical and behavioral studies to identify, synthesize, and field test the sex attractant pheromone of adult Melanotus verberans, the larvae of which are important crop pests. In coupled gas chromatography-mass spectrometry analyses of extracts of ovipositors of females, five possible pheromone components were identified. Subsequent coupled gas chromatography-electroantennogram detection analyses indicated that male antennae were responsive to only two of these compounds, 13-tetradecenyl acetate and 13-tetradecenyl hexanoate. In field trials, neither compound alone was attractive, but a blend of the two was strongly attractive to conspecific male beetles, and did not attract other species. A two-year field study showed that most male beetle flight activity occurred from April through May. Because the sex pheromone of M. verberans consists of two compounds that can be readily synthesized, its development for integrated pest management should be economically feasible.