Sampling Abundances of Soybean Arthropods: Comparison of Methods12

Abstract

Direct observation (DO) of arthropods on soybean plants was compared to another absolute method, clam trap (CT), and to sweepnet (SW) sampling during a season-long investigation of the colonization by arthropods of 2 east central Illinois soybean fields. DO was similar to CT sampling in numbers of individuals detected per m of row. Numbers detected by DO were much greater than those detected by SW sampling. Population trends for a given arthropod species showed better agreement in the DO-CT comparison than in the DO-SW comparison. Proportion of similarity (PS) values for the DO-CT comparison were higher than those for DO-SW. In general, on the basis of numbers of individuals detected, DO sampling compared much more favorably with the other absolute method, CT sampling, than it did with the relative method of SW sampling.