Environmental Entomology (1991) 20, 1711-1719

Steve H. Dreistadt and Donald L. Dahlsten (1991)
Establishment and overwintering of Tetrastichus gallerucae (Hymenoptera: Eulophidae), an egg parasitoid of the elm leaf beetle (Coleoptera: Chrysomelidae) in northern California
Environmental Entomology 20 (6), 1711-1719
Abstract: Tetrastichus gallerucae (Fonscolmbe), an egg parasitoid of the elm leaf beetle, Xanthogaleruca luteola (Miller), apparently has failed to become established at most sites in 15 northern California counties where it was introduced from 1974 to 1989. Established T. gallerucae populations are low or undetectable until late in the season. Poor establishment is due to poor survival during the host-free period, and the life stage and habitat of T. gallerucae overwintering is unknown. Degree-day modeling indicates that adults, and at some locations immatures, can survive the host-free period in a state of quiescence. However, laboratory and field studies reveal that few parasitoids possess the longevity to overwinter successfully. The T. gallerucae strains introduced to date in northern California appear to lack the temperature adaptations necessary to survive the host-free period in sufficient numbers to provide early-season biological control of elm leaf beetle.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
population dynamics/epizootiology
classical biocontrol/new introduction

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Xanthogaleruca luteola		U.S.A. (SW)
Oomyzus gallerucae (parasitoid)	Xanthogaleruca luteola		U.S.A. (SW)