POPULATION ASSESSMENT DURING THE LARVAL STAGE OF THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE)

Abstract

AbstractThis paper presents a sampling plan for estimating numbers of H. postica larvae in the spring growth of alfalfa. A 6-stem bouquet of foliage formed an appropriate sample unit. The pattern of counts for all four instars conformed to the negative binomial distribution, and variance analysis for 89 sets of data revealed that differences between block, plots, and quadrats generally were not significant. For moderate levels of infestation (ca. 12 larvae per bouquet), estimates with acceptable precision may be obtained by taking a single 6-stem bouquet from each of 16 randomly selected ft2 (0.9m2) quadrats within a field, at a total cost of 120 man-minutes.