Submitted to: International Society of Chemical Ecology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 7/12/2001
Publication Date: N/A
Technical Abstract: We are investigating the semiochemical cues used by geographically isolated strains of Telenomus podisi to find eggs of stink bugs in the genus Euschistus. Two strains of T. podisi are being maintained at Beltsville on eggs of the South American species, Euschistus heros; one parasitoid strain originated from specimens collected near Brasilia, Brazil (SA strain), and a second strain originated from specimens collected at Beltsville, Maryland (NA strain). Preliminary evidence indicates that both strains are attracted to the vicinity of Euschistus spp. by host allomone and/or pheromone compounds. Furthermore, experiments using E. heros showed that SA T. podisi females specifically recognize traces left on the substrate by walking E. heros females and then intensively search the area of the "footprints", apparently looking for an egg mass to parasitize. On the contrary, NA T. podisi females are incapable or recognizing the footprints of E. heros females, despite the fact that these parasitoids were reared from eggs of E. heros. Separated experiments testing the cold tolerance of the NA and SA T. podisi strains demonstrated that NA T. podisi females are extemely cold tolerant (>80% survival after 5 days at - 4 degrees C), a trait which facilitates handling of this potential biological control agent. Efforts are underway to identifiy the footprint contact pheromone and to artificially select a T. podisi strains combining cold tolerance and complete semiochemical recognition of E. heros, with the hope of utilizing this improved parasitoid strain for biocontrol of E. heros in Brazil and Euschistus spp. in the U.S.