Free flight of western corn rootworm (Coleoptera : Chrysomelidae) to corn and soybean plants in a walk-in wind tunnel

Oviposition in soybean fields by western corn rootworm, Diabrotica virgifer a virgifera LeConte, is threatening the effectiveness of crop rotation in e ast-central Illinois and adjoining counties in northwestern Indiana. Attrac tion to soybean, Glycine max L., plants has been hypothesized as a mechanis m underlying rootworm oviposition in soybean fields. In this study, female western corn rootworms were allowed to fly freely for 0.5 h within a wind r unner array of potted soybean and corn, Zea mays L, plants before rootworm distribution patterns on corn and soybeans were determined. Test insects we re collected in corn and soybean plantings om bath within and outside of ar eas where adults oviposit in soybean fields. We found no evidence of an inc reased tendency for rootworms from various populations to be associated wit h soybeans regardless of collection location, cropping history at the colle ction site, or the area's status with respect to western corn rootworm ovip osition in soybean fields. The difference between corn and soybean plant he ight influenced postflight distribution of adults in the Hind tunnel. More rootworms accumulated on plants whose foliage projected above the height of the insect release platform. Distance moved during a 0.5-h period of free flight was greatest when the foliage of nearby plants did not extend above the level of the insect release platform. Regardless of how corn and soybea n plants were configured in the wind tunnel, a significantly greater propor tion of rootworms was recovered on corn plants. We found no evidence for at traction to soybeans based on postflight plant association.