Mixed sex pheromone lures for combined captures of Agriotes and Limonius pest click beetles in North America

Sex pheromone lures are effective tools for monitoring and potentially controlling populations of pest click beetles (Coleoptera: Elateridae). To date, these lures are genus-specific (e.g., Limonius spp.) or species-specific (e.g., Agriotes lineatus Linnaeus). However, if sympatric heterogeners were not to be repelled by each other's pheromones, trap lures effective for multiple elaterid genera could be developed, improving cost efficiency in elaterid pest management programs. In both western and eastern North America, several species of Agriotes spp. and Limonius spp. co-occur and inflict similar crop damage. We investigated whether the sex pheromones of these species can be combined in a mixed lure without reducing its attractiveness to all target species. In western Canada, we show that the pheromones of A. lineatus (geranyl butanoate & geranyl octanoate) and Limonius spp. [(E)-4-ethyloct-4-enoic acid (limoniic acid)] can be combined without significantly reducing captures of male A. lineatus, L. canus (LeConte), L. californicus (Mannerheim) and L. infuscatus (Motschulsky) relative to traps baited with species-specific lures for A. lineatus and Limonius spp.. Similarly, the pheromone of A. obscurus (Linnaeus) (geranyl hexanoate & geranyl octanoate) and limoniic acid can be combined without significantly reducing trap captures of male L. canus, L. infuscatus and L. californicus but reduced A. obscurus captures relative to traps baited only with the A. obscurus pheromone. In eastern Canada, combining pheromones for Agriotes mancus (Say) (geranyl butanoate & geranyl hexanoate) and limoniic acid reduced captures of A. mancus but not A. pubescens (Melsheimer) and A. sputator (Linnaeus). These data imply that pheromones of select elaterid heterogeners can be combined in a 'catch-more' pheromone lure to effectively monitor for, or possibly control, multiple elaterid pests, but that such mixed lures should be evaluated for each species combination.