Canadian Forest Service Publications

Sampling the egg stages of the two-year-cycle spruce budworm near Babine Lake, British Columbia. 1963. Harris, J.W.E. Forestry Chronicle 39(2): 199-204.

Year: 1963

Issued by: Pacific Forestry Centre

Catalog ID: 23913

Language: English

Availability: PDF (download)

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Abstract

Methods of sampling the immature stages of the two-year-cycle spruce bud-worm, Choristoneura fumiferana (Clem.), were studied at Babine hake in west-central British Columbia; this paper deals with the egg stage. At high population levels there was no difference in the number of egg masses per square foot of foliage surface between hosts, study areas, direction or sample size. Significant differences existed between crown levels and trees. Samples from understory trees were not representative of the egg populations from overstory trees. An acceptable estimate of egg numbers may be obtained by sampling one 18-inch branch tip from the mid-crown portion of as many trees as possible. Significant differences between sample areas at low population levels indicate that more localities would have to be sampled to obtain a representative estimate of egg numbers when fewer insects are present.

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