Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/12/2007
Publication Date: 10/28/2007
Citation: Leopold, R.A., Chen, W. 2007. The expression of chilling injury in the progeny of the parasitic wasp, Gonatocerus ashmeadi. J.C. van Lenteren, P. DeClercq & M. Johnson, 2007. Precedings of 11th meeting of the Working Group Arthropod Mass Rearing and Quality Control, 28 October - 1 November 2007, Montreal, Canada. Bulletin IOBC Global No. 3, p. 78-81.
Technical Abstract: Gonatocerus ashmeadi, is an egg parasitoid that attacks Homalodisca vitripennis (Germar), the glassy-winged sharpshooter (GWSS), a vector of Pierce’s disease. This parasitoid and related species are being mass-reared and tested for possible use in aiding in the control of GWSS. As an aid to mass-rearing of the GWSS and its parasitoids, we have developed several cold storage protocols for these insects. Because extended chilling of organisms can produce harmful side affects, we examined the post-storage quality of the parental through the F2 generation of G. ashmeadi using either GWSS eggs stored before parasitization or as immatures within their host eggs. Our studies showed that GWSS egg masses purposely killed by chilling can be stored up to 35 days and >70% were readily accepted by G. ashmeadi as hosts. Further, >80% of the subsequently parasitized eggs yielded wasp progeny. GWSS eggs parasitized by G. ashmeadi can be stored up to 20 days without affecting emergence, survival, development, or progeny quality through the F2 generation. After 30 d of storage, survival of the parental generation was decreased by 24%, the developmental time was extended 4 d, and the fecundity of the F1 females decreased by 32%. After 40 d of storage, only 12% of the wasps emerged from their host eggs, 44% of the females were sterile, and the production of males by the non-sterile females increased by 155%. The F1 female progeny of these stored parents subsequently exhibited a 70% reduction in parasitism of host eggs and a 73% decrease in overall fecundity. Chilling also delayed the peak emergence of the parents but not of either the F1 or F2 generations. Examination of the F1 and F2 populations by demographic analysis also confirmed that the F1 generation was affected by 30 d of chilling of the parents but the damage did not extend to the F2 generation.