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POPULATION AND MORTALITY ASSESSMENT DURING THE COCOON STAGE OF THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE)1
Published online by Cambridge University Press: 31 May 2012
Abstract
This paper presents a sampling plan for estimating populations of Hypera postica (Gyll). cocoons in alfalfa, and of the principal mortality factors during this stage. The plan provides for samples in foliage and ground litter. For samples in foliage, where two-thirds of the cocoons are found, the most appropriate sample unit is a bouquet of 6 stems; for typical weevil densities, estimates with acceptable precision may be obtained by taking 25 bouquets at random from within a field. For litter samples, the appropriate sample unit is a quarter ft2 (232 cm2); acceptably precise estimates may be obtained by taking 20 such units at random from within a field. Total cost for a combined sample is 3.9 man-hours.
The pattern of counts, both in foliage and ground litter, was well described by the negative binomial distribution.
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- Copyright © Entomological Society of Canada 1975
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