Sex pheromone of the alfalfa plant bug, Adelphocoris lineolatus: perspectives and practical considerations (Hemiptera: Miridae)

Abstract: The alfalfa plant bug, Adelphocoris lineolatus is an important pest of alfalfa seed
production and it may cause considerable damage to several other crops as well. Due to the
economic importance of the species, research on its chemical ecology is of special importance
as it may offer novel tools for monitoring or potentially for pest management purposes. The sex pheromone of A. lineolatus was first identified based on studies on East-Asian populations of the species. Nevertheless, sex pheromone composition may differ in different geographic regions in species with wide distribution (e. g., Lygus pratensis).
In the course of our studies on Central European populations of A. lineolatus we performed
air entrainments and identified potential sex pheromone components, which were tested later on in field experiments. In search for a potential synergistic effect, the sex pheromone was also tested in combination with a previously known floral attractant, (E)-cinnamaldehyde.
From air entrainment samples hexyl-butyrate, (E)-2-hexenyl-butyrate and (E)-4-oxo-2-
hexenal were identified, and based on field experiments sex pheromone composition of Central European A. lineolatus populations was found to be similar to East-Asian populations. Furthermore, 1-hexanol was identified as a potential sex pheromone antagonist, this compound decreased attraction of male A. lineolatus to the sex pheromone considerably. When the sex pheromone was tested in combination with (E)-cinnamaldehyde, number of attracted males did not show significant increase as compared to the sex pheromone alone, however, females were attracted irrespective of the presence of the sex pheromone. Perspectives of the results in respect of potential agricultural applications are discussed.