Pheromone combination lures for Carpophilus (Coleoptera: Nitidulidae) species.

Combinations of aggregation pheromones for 3 nitidulid beetle species, Carpophilus hemipterus (L.), C. mutilatus Erichson, and C. freemani Dobson, were evaluated as trap baits in a date garden in southern California. All possible 2- and 3-way combinations were compared with the single pheromones; fermenting whole wheat bread dough was present with all pheromone treatments as a synergist, and dough by itself was the experimental control. Each species was strongly attracted to its own pheromone, and species specificity of the pheromones was high. Generally, responses to conspecific pheromones were not inhibited by the presence of other pheromones. Only for C. freemani was the 3-pheromone combination significantly less attractive than species pheromone tested alone, but the combination was still more attractive to C. freemani than the control. A subsequent wind-tunnel study confirmed that the response of C. freemani to its pheromone could be reduced when the major component of the C. mutilatus pheromone was present. Two minor species at the test site, C. obsoletus Erichson and C. (Urophorus) humemlis (F.), exhibited significant cross attraction to the pheromones of the major species in the field. This cross attraction was not hindered by the presence of pheromone combinations. The demonstrated effectiveness of the pheromone combinations would simplify the use of the pheromones for mass trapping. One multispecies lure type would replace a series of specific lures for individual species with no or slight loss of efficacy for any target species.