Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 8, 1999
Publication Date: N/A
Technical Abstract: The southern green stink bug (SGSB), Nezara viridula (Hepteroptera: Pentatomidae), is a serious agricultural pest worldwide. Its host range includes soybean and other field crops, a variety of fruits and nuts, and many vegetables (Westcott 1964). The parasitoid fly, Trichopoda pennipes (Diptera: Tachinidae), is the only native tachinid fly that has naturally adopted the SGSB as a host since its accidental establishment in the southeastern U.S. some 200 years ago. However, T. pennipes introduced into Hawaii from Florida failed to parisitize N. viridula, and T. pennipes fails to attack the squash bug, Anasa tristis (Coreidae), in California although A. tristis is the most common host of this parasitoid in the northeastern U.S. (Pickett et al., 1996). These observations suggest that different strains of T. pennipes exist in the U.S. Sexually mature males of N. viridula release a sex pheromone containing isomers of the sesquiterpenoid, ,1,2-epoxy-(Z)-alpha-bisabolene (Aldrich et al., 1987). We report here tha geographically isolated populations of T. pennipes gave dramatically different antennal responses to pheromone extracts of N. viridula and certain native host species. This is the first experimental verification that kairomone-strains of T. pennipes exist and demonstrates that electro physiological screening of parasitoids prior to classical biological control introductions could avoid inevitable failures. In addition, we have found that the antennae of tachinid parasitoids are commonly 5 to 10 times more sensitive to the pheromone of their hosts than are the antennae of the host species themselves. Therefore we plan to try to use the antennae of the T. pennipes strain that prefers to parasitize squash bugs as a means to identify the sex pheromone of this pest.