To maximize results from labor effort, samples for egg and larval populations of the northern corn rootworm, Diabrotica longicornis (Say), and the western corn rootworm, D. virgifera LeConte, have been taken at the sites of population concentrations. While the results of such samples are useful on a relative basis, they do not show the densities as number of eggs or larvae per acre. The densities of eggs and larvae in different locations in the space occupied by a plant hill were determined. Based upon these densities. the factors to convert the numbers of eggs and larvae in concentrated samples to the number per acre were developed. Under the conditions of the study, the factors are: (a) The number of eggs per acre in 40-in. rows = the number of eggs per 4-in. core, taken next to and south of the plant hill, X 8 X the number of hills per acre. (b) The number of larvae per acre in 40-in. rows = the number of larvae per 5-qt sample taken over the plant, X 2.5 X the number of plants per acre. (c) The number of larvae per acre in 30-in. rows = the number of larvae per 5-quart sample taken over the plant, X 1.9 X the number of plants per acre.
Document Type: Research Article
Publication date: June 1, 1969
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Journal of Economic Entomology is published bimonthly in February, April, June, August, October, and December. The journal publishes articles on the economic significance of insects and is divided into the following sections: apiculture & social insects; arthropods in relation to plant disease; forum; insecticide resistance and resistance management; ecotoxicology; biological and microbial control; ecology and behavior; sampling and biostatistics; household and structural insects; medical entomology; molecular entomology; veterinary entomology; forest entomology; horticultural entomology; field and forage crops, and small grains; stored-product; commodity treatment and quarantine entomology; and plant resistance. In addition to research papers, Journal of Economic Entomology publishes Letters to the Editor, interpretive articles in a Forum section, Short Communications, Rapid Communications, and Book Reviews.