Farm Progress Reports




Northeast Research and Demonstration Farm




Cross-resistance occurs when resistance to one insecticide confers resistance to additional insecticides. Past research has found that western corn rootworm populations in Iowa are resistant to three of the four rootworm Bt traits (Cry3Bb1, mCry3A, and eCry3.1Ab) because of cross-resistance among these traits. The purpose of this study was to better understand the effects of cross-resistance in the field. The Northeast Research and Demonstration Farm represents an area in Iowa in which Cry3Bb1 resistance by western corn rootworm has been present since 2009. To further characterize the effect of Bt-resistance on corn rootworm management, we measured root injury to Agrisure Duracade (mCry3A + eCry3.1Ab), DeKalb YieldGard VT Triple (Cry3Bb1), and Pioneer HXX (Cry34/35Ab1).



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