Staff “We need to minimize selection of bollworms on Vip proteins as much as possible,” Sebe Brown said. Entomologists encourage producers to be aware of older Bt traits as insect resistance begins to wane. The No.1 variety consideration for cotton growers is to choose one that performs well under specific locations and field conditions. Yield and quality pay the bills. Entomologists encourage producers to also be aware of some of the older traits (Cry1 and Cry2) as insect resistance begins to wane. “Things have not gotten worse,” said Scott Stewart, University of Tennessee Institute of Agriculture. "And the Cry2 traits still have a place, but producers planting those varieties may need to spray for bollworms if pressure is high or sustained."