Hybrid megapests in Brazil are spreading pesticide resistance

Mar 20th 2026

Genomic analysis shows the two major crop pests have exchanged genes that confer resistance to Bt toxins and pyrethroid insecticides, threatening Bt soya effectiveness in Brazil and raising global food security risks.

  • The cotton bollworm (Helicoverpa armigera) and the corn earworm (H. zea) have hybridised in Brazil since H. armigera arrived around 2013 and hybrids were first detected genetically in 2018.