Combining plant volatiles and pheromones to catch two insect pests in the same trap: Examples from two berry crops.

Summary

Most horticultural crops are attacked by more than one insect pest. As broad-spectrum chemical control options
are becoming increasingly restricted, there is a need to develop novel control methods. Semiochemical attractants
are available for three important horticultural pests, strawberry blossom weevil, Anthonomus rubi Herbst
(Coleoptera: Curculionidae), European tarnished plant bug, Lygus rugulipennis Poppius (Hemiptera: Miridae) and
raspberry beetle, Byturus tomentosus deGeer (Coleoptera: Byturidae). Traps targeting more than one pest species
would be more practical and economical for both monitoring and mass trapping than traps for single-species. In this study we aimed to (1) improve the effectiveness of existing traps for insect pests in strawberry and raspberry crops by increasing catches of each species, and (2) test if attractants for two unrelated pest species could be combined to capture both in the same trap without decreasing the total catches. Field tests were carried out in four European countries and different combinations of semiochemicals were compared. A volatile from strawberry flowers, 1,4 dimethoxybenzene (DMB), increased the attractiveness of the aggregation pheromone to both
sexes of A. rubi. The host-plant volatile, phenylacetaldehyde (PAA), increased the attraction of female L. rugulipennis to the sex pheromone, and, in strawberry, there was some evidence that adding DMB increased catches further. Traps baited with the aggregation pheromone of A. rubi, DMB, the sex pheromone of L. rugulipennis and PAA attracted both target species to the same trap with no significant difference in catches compared to those single-species traps. In raspberry, catches in traps baited with a combination of A. rubi aggregation pheromone, DMB and the commercially available lure for B. tomentosus, based on raspberry flower volatiles, were similar to those in single-species traps. In both crops the efficiency of the traps still needs improvement, but the multispecies traps are adequate for monitoring and should not lead to confusion for the user as the target species are easy to distinguish from each other.