ARS | Publication request: Grape hosts infested with glassy-winged sharpshooters produce volatile compounds which may attract egg parasitoids

Submitted to: American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2011
Publication Date: June 1, 2011
Citation: Wallis, C.M., Krugner, R., Walse, S.S. 2011. Grape hosts infested with glassy-winged sharpshooters produce volatile compounds which may attract egg parasitoids. Phytopathology 101:S184.

Technical Abstract: Glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar), is an important vector of Xylella fastidiosa Wells, which causes Pierce’s disease in grapes. Current management strategies in GWSS infested areas include mass release of the egg parasitoid Gonatocerus ashmeadi Girault and related species. However, little is known about egg parasitoid host finding behavior. Thus, volatile emissions from non-infested grapes and grapes infested with GWSS egg masses were compared using gas chromatography and mass spectrometry. Three compounds, tentatively identified as beta-ocimene, (1, 8)-cineole, and beta-farnesene, were emitted in greater levels from grape hosts infested with GWSS egg masses than non-infested plants. Parasitoid attraction to synthetic versions of these compounds will be evaluated. If confirmed to be attractants for the egg parasitoids, these compounds could be deployed as lures to monitor egg parasitoid populations in a locale. These compounds also could be screened in grape breeding programs aimed at reducing GWSS populations, because infested grapes producing more of these compounds will improve attractiveness to the parasitoids that prey on GWSS eggs.