Occurrence of molecularly diverse Bt Cry toxin-resistant mutations in insect pests of Bt+ corn and cotton crops and remedial approaches

Abstract

Cultivation of Bt + genotypes has dispensed with insecticidal sprays and thereby corn and cotton farmers have hugely benefited worldwide. Recent recordings of genetically diverse Cry-resistance in insect pests of Bt + corn and cotton fields have raised grave concern. Curiously, bulk of Cry-resistant pink bollworms found in certain Bt + cotton fields in India proved homozygous for multiple linked mutations. Besides, dominantly inheritable Cry-resistance and cross resistance between different Cry-proteins have also been noted. To stem evolution of resistance against anti- insect protein-toxins, new nematology research on IPM procedures, complementary to refuge and Cry stacking technologies is imminently needed.