SAMPLING METHODS FOR ARTHROPOD COLONIZATION STUDIES IN SOYBEAN

Abstract

Direct observation (DO) of arthropods on soybean plants was compared with another absolute method, clam trap (CT), and with sweepnet (SW) sampling during a season-long investigation of the colonization by arthropods of two east central Illinois soybean fields. In terms of number of species detected, DO vs. CT showed good agreement between the two fields, while DO vs. SW showed poor between-field agreement. Proportion of similarity (PS) and quotient of similarity (QS) values were higher in a DO-CT comparison than in a DO-SW comparison. Performance similar to that of the other absolute method, consistency of results, ability to use the method throughout the entire season, relatively high numbers of species and individuals detected per unit area sampled, relatively short time required to sample a site, and the capability of yielding a precise record of important interactions among soybean arthropods indicate that direct observation is an effective method for sampling the arthropod community on a row crop such as soybean.