Overwintering biology, food supplementation and parasitism of eggs of Homalodisca coagulata (Say) (Homoptera : Cicadellidae) by Gonatocerus ashmeadi Girault and Gonatocerus Morrilli (Howard) (Hymenoptera : Mymaridae)

• Author(s): Andersen, Peter; Brodbeck, Brent; Lopez, R.; Mizell, Russell;
• Abstract: The efficiency of parasitism of Gonatocerus ashmeadi Girault and G. morrilli (Howard) (Hymenoptera: Myramidae) on glassy-winged sharpshooter, Homalodisca coagulata (Say) (Homoptera: Cicadellidae), eggs of varying age was documented. Excised leaves with H. coagulata eggs of age 1 to 9 d were presented to mated female parasitoids in Petri dishes as well as on intact foliage. Parasitism rates for both species were high with 3 females in Petri dishes parasitizing virtually all eggs in 3 egg masses, and 8 mated females finding and parasitizing almost all eggs from 5 egg masses in small shrubs of Ilex opaca cv cornuta. For both species, parasitism efficiency exceeded 95% within 24 h. Parasitism rates declined for older eggs (8 and 9 d) on excised leaves. Because this did not occur on live plant material, hardening of excised foliage likely contributed to lower rates of parasitism. No cases of superparasitism were observed: Overwintering of the parasitoids was examined by monitoring the fate of eggs of H. coagulata deposited in November. We documented the first case of H. coagulata overwintering as eggs under North Florida conditions. In addition, both G. ashmeadi and G. morrilli were able to overwinter as undeveloped larvae within parasitized eggs under similar conditions. Overwintering parasitoids took approximately 85 d for emergence, which slightly exceeded the minimum predicted for emergence by existing degree day models. Feeding experiments conducted with G. ashmeadi and G. morrilli as food sources are limited during winter/spring; however, our results confirmed that honeydew from Dialeurodes citri (Ashmead) (available in North Florida in late winter/early spring) significantly increased the longevity of both parasitoid species when compared to honey and water.
• Publication Date: Apr 2004
• Journal: Journal Of Entomological Science