Functional loss of CHS2 confers high‐level resistance to Bacillus thuringiensis Vip3Aa in Spodoptera exigua and Agrotis ipsilon

These findings further validate the essential role of the CHS2 gene-and the PM it produces-in Vip3Aa toxicity. Complete knockout confers high resistance but imposes severe fitness costs, suggesting that such alleles are unlikely to persist in natural populations. This study advances our understanding of the molecular mechanisms behind resistance to Vip3Aa and provides insights for developing effective resistance management strategies in Bt crop management. © 2025 Society of Chemical Industry.