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EVIDENCE FOR MORTALITY IN ADDITION TO SUCCESSFUL PARASITISM OF NEEDLEMINING LARCH CASEBEARER (LEPIDOPTERA: COLEOPHORIDAE) LARVAE BY AGATHIS PUMILA (RATZ.) (HYMENOPTERA: BRACONIDAE)

Published online by Cambridge University Press:  31 May 2012

R.B. Ryan
R.B. Ryan
Affiliation:
Forestry and Range Sciences Laboratory, Pacific Northwest Research Station, Forest Service, U.S. Department of Agriculture, La Grande, Oregon, USA97850
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Extract

In an attempt to control the larch casebearer, Coleophora laricella (Hübner), in western North America with biological agents, insect parasites from Europe and Japan were introduced (Denton 1972, 1979; Ryan et al. 1987). The braconid Agathis pumila (Ratz.) has become widely established and apparently has been responsible for markedly reduced casebearer densities (Ryan 1983, 1986; Ryan et al. 1987). Parasitization by it in many research plots reached 80-95% (unpublished data), then declined following reductions in the casebearer populations in a typically delayed density-dependent manner. I present here a partial explanation for why casebearer densities declined so drastically, to levels even lower than could perhaps be explained by parasitization at such high levels.

Type
Articles
Information
The Canadian Entomologist , Volume 120 , Issue 11 , November 1988 , pp. 1035 - 1036
Copyright
Copyright © Entomological Society of Canada 1988

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References

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