Also known as the corn earworm, the cotton bollworm has spent the last decade steadily evolving resistance to most of the corn and cotton Bt proteins on the market that target it.
Now, entomologists across the South are reporting increased feeding and survival in Bt corn and cotton fields expressing the Vip3A protein, once believed to be the final Bt stronghold against this pest. Texas scientists are testing some of these suspect bollworm populations for resistance.
In the past few years, researchers have documented resistance in the bollworm/earworm to some of the older Bt Cry proteins found in three-gene cotton varieties (Bollgard 3, TwinLink Plus and Widestrike 3) and pyramided corn hybrids (Viptera, Leptra and Trecepta). That has put tremendous selection pressure on the Vip3A protein in these varieties and hybrids, entomologists told DTN.
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Read full, original article: Bollworm Battle Continues
