Aspen Bibliography

The influence of stand factors on parasitism of spruce budworm eggs by Trichogramma minutum

Document Type

Article

Journal/Book Title/Conference

Environmental Entomology

Volume

7

Issue

5

First Page

685

Last Page

688

Publication Date

1978

Abstract

Data included intensive information on stand density, composition, age, crown closure, crown surface area, basal area, height, and associated vegetation across a 60-plot ecological continuum in Maine. T-test results showed significantly higher numbers of egg masses, viable eggs, non-viable eggs, parasitized eggs, and percent parasitism in the upper crowns when compared to mid-crown levels ( P < 0.05). Regression analyses indicated that parasitism rates rose with increasing density of nonbudworm host tree species, especially hardwoods such as sugar maple ( Acer saccharum Marshall), yellow birch ( Betula alleghaniensis Britton), paper birch ( B. paprifera Marshall), red maple ( A. rubrum L.), hop hornbeam ( Ostrya virginiana (Miller) Koch), and big tooth aspen ( Populus grandidentata Michaux). It appears that increases in parasitism are due to greater numbers of alternate parasite hosts found in more diverse habitats.

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