OPTIMAL SAMPLE SIZE FOR THE ESTIMATION OF SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) POPULATIONS ON BALSAM FIR AND WHITE SPRUCE

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Abstract
An equation is presented for the determination of sample sizes needed to estimate with a given precision the larval population density of spruce budworm on balsam fir and white spruce branch tips in Ontario. This equation is primarily applicable to low densities, but is valid to a density of 50 larvae/branch tip. The distribution of budworm larvae at densities below 0.1/branch tip is nearly random, and is aggregated at higher densities. Their distribution is the same on the two host species.