Environmental Entomology (2012) 41, 1115-1124

Nathan W. Siegert, Deborah G. McCullough, Micheal M. Wheeler and Ann E. Hajek (2012)
Evaluation of potential versus realized primary infection of gypsy moth (Lepidoptera: Lymantriidae) by Entomophaga maimaiga (Zygomycetes: Entomophthorales)
Environmental Entomology 41 (5), 1115-1124
Abstract: The fungal entomopathogen Entomophaga maimaiga has provided important biological control of gypsy moth, Lymantria dispar (L.), since the first epizootics occurred in the northeastern United States in 1989. Epizootics are initiated by germination of soil-borne resting spores, which are highly sensitive to spring temperature and moisture. We compared gypsy moth infection by E. maimaiga in 33 oak stands in Michigan with infection under optimal laboratory conditions from 1999 to 2001 to assess differences between potential and realized efficacy of E. maimaiga. Field bioassays were conducted by exposing laboratory-reared, fourth-instar gypsy moth to soil at the base of oak trees for 4 d. Additional larvae were similarly exposed to soil collected from the field plots in laboratory bioassays with temperature, humidity, and moisture levels optimal for fungal germination. Overall E. maimaiga infection ranged from means of 3.2-29.8% in the field compared with 20.9-59.7% in the laboratory during three field seasons. Resting spore density in soil and gypsy moth egg mass density were significant predictors of field infections in two of the 3 yr, whereas resting spore density was a significant predictor of laboratory infections each year. Other variables that significantly predicted laboratory infections in one of the 3 yr included egg mass density, canopy cover, and soil pH. In laboratory bioassays, soil pH and E. maimaiga resting spore density were positively associated with increasing E. maimaiga infection rates of gypsy moth larvae.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Nathan W. Siegert, Ann E. Hajek, Deborah G. McCullough

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
population dynamics/epizootiology
environment/habitat manipulation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Lymantria dispar	Oak (Quercus)	U.S.A. (NE)
Entomophaga maimaiga (entomopathogen)	Lymantria dispar	Oak (Quercus)	U.S.A. (NE)