EVALUATION OF SAMPLING METHODS FOR LADY BEETLES (COLEOPTERA, COCCINELLIDAE) IN GRAIN-SORGHUM

Four sampling techniques (visual counts on 50 plant samples, sweepnet, drop cloth, and pitfall traps) were evaluated over a 3-yr period to determine the most efficient methods in terms of time, effort, and precision for estimating coccinellid population densities in grain sorghum. Correlations were made among the four techniques, using visual counts as the absolute method, and estimates were made of the relative sampling variation (precision) and relative net precision (efficiency) for each technique. Visual counts were the most efficient sampling method when high precision is desired, regardless of time constraints. When time is a constraint, the drop cloth method is most precise and efficient, followed by sweepnet sampling.