LAUSR

Abstract Parasitoid wasps may rely on chemical volatiles from herbivorous insects and their plant hosts for finding their preferred host. This study was conducted to test the reaction of Trichogramma papilionis Nagarkatti (Hymenoptera: Trichogrammatidae) to chemical volatiles that from host eggs and egg infested plants. Several volatile compounds were selected, singly, and as combinations of chemicals to determine whether these volatile compound blends could enhance orientation responses of T. papilionis wasps toward the source of the stimulus. In a Y-tube olfactometer, female wasps were significantly attracted to only two chemical volatiles among the seven compounds tested. The compounds were: trans-isoeugenol, anisole, β-myrcene, cis-3-Hexenyl butyric acid (bis(2-ethylhexyl) phthalate, bis(2-ethylhexyl) phthalate, acetophenone, and α-farnesene (> 95% purity). Only anisole and bis(2-ethylhexyl) phthalate were attractive to T. papilionis wasps when used separately in olfactometer experiments. The wasps showed a significant attraction to a blend of anisole and bis(2-ethylhexyl) phthalate at a ratio of 25μL/100μL. There was no significant response to the other bled ratios of that combination of chemicals. Greenhouse studies showed that the wasps were not significantly attracted to anisole alone, but exhibited short-distance attraction to the above blend.