IDENTIFICATION OF THE NATIVE PARASITOID FAUNA ASSOCIATED WITH GRAPHOCEPHALA ATROPUNCTATA AND HOST SPECIFICITY TESTING OF GONATOCERUS ASHMEADI ON HOMALODISCA LITURATA

• Author(s): Hoddle, Mark; Boyd, Elizabeth; Triapitsyn, Serguei;
• Abstract: To determine the oviposition preference of female blue-green sharpshooters (BGSS), Graphocephala atropunctata (Signoret) (Hemiptera: Cicadellidae), a survey was conducted on southern California wild grape, Vitis californica Benth (Vitaceae) growing near Temecula, California in August 2003 where populations of BGSS were known to occur. Female BGSS oviposited into new growth, primarily the succulent tendrils and stems. The under sides of small leaves and petioles were also used for oviposition, but to a lesser extent. Mature stems, large and medium sized leaves and petioles were not utilized for oviposition. Two parasitoids, Gonatocerus latipennis Girault and a Polynema sp. (Hymenoptera: Mymaridae) were reared from BGSS eggs. Literature reviews revealed a deficiency of known natural enemies for G. atropunctata. A sentinel plant study was conducted to further confirm the parasitization of BGSS eggs by these parasitoids. Collectively the Polynema sp. and Gonatocerus latipennis constitute the first documented parasitic natural enemies of BGSS eggs. A further examination, commencing in January 2004, of the activity of BGSS and its parasitoids in southern California is currently underway. Blue-green sharpshooter adult activity reached its peak in July while bi-weekly samples of wild grape canes and tendrils revealed peak emergence of blue-green nymphs and parasitoids occurred from mid-July to mid-August. No-choice tests with Gonatocerus ashmeadi Girault, a parasitoid of the galssy-winged sharpshooter, Homalodisca coagulata, and BGSS eggs as part of a non-target impact assessment have yielded few results thus far. However, no-choice tests with G. ashmeadi and the native smoke-tree sharpshooter (STSS), Homalodisca liturata Ball, yielded no significant differences in percent parasitism of eggs when compared to the GWSS control.
• Publication Date: Dec 2004
• Journal: 2004 Pierce's Disease Research Symposium