HOST SELECTION AND LOW TEMPERATURE STORAGE OF THE GLASSY-WINGED SHARPSHOOTER, HOMALODISCA COAGULATA

• Author(s): Yocum, Roger; Chen, Wenlong; Lauziere, Isabelle; Morgan, David;
• Abstract: The egg parasitoid, Gonatocerus ashmeadi, is a mymarid wasp that accounts for most of the observed parasitism in California on the glassy-winged sharpshooter (GWSS), Homalodisca coagulata (Say), a vector for Pierces disease. In the absence of techniques for propagating the wasp via artificial methods, it is very important to mass-rear the GWSS to provide host eggs for this parasite to be used in bio-control programs. Low temperature storage is an integral part of the process of mass-rearing insects for use in agricultural pest control programs (Leopold 1998). Through cold storage, parasitized and unparasitized GWSS eggs may be accumulated and held for later use in rearing and releasing parasitoids. Although Al- Wahaibi and Morse (2002, submitted) reported that the development of GWSS eggs held at 11.5 C was retarded and aborted during early stages of eye spot formation, data regarding the effect of low temperature throughout the development of the GWSS and that of the egg parasitoid are lacking. Further, choosing suitable host plants, which are amenable to cold storage, will be very critical for establishing and maintaining the leafhopper colony and for obtaining large numbers of leafhopper eggs. The sharpshooter is a highly polyphagous leafhopper having over 100 known host plants in Florida (Adlerz 1979). Recent observation shows that the leafhopper can feed on at least 72 plant species in 37 families (Hoddle at al. 2002, submitted), and 73 plant species in 35 families (Blua et al. 1999). Although feeding is apparently limited to xylem vessels on all host plants (Anderson et al. 1989), some studies have shown that the leafhopper exhibits host-plant preference (Adlerz 1979; Mizell and French 1987), and that the amide concentrations in host plants may potentially cause an oviposition preference by the leafhopper (Andersen et al. 1992). Some field observations have indicated the preference for different plant species varied with different times of the year (Adlerz 1979; Mizell and French 1987; Brodbeck et al. 1990). However, little quantitative data are available so far on host plant preference of feeding adult males and females under laboratory or mass-rearing conditions.
• Publication Date: Dec 2002
• Journal: 2002 Pierce's Disease Research Symposium