Development of insecticide resistance and cross‐resistance in fenvalerate‐, and cypermethrin‐selected strains of Earias vittella(fab.)

First‐instar Earias vittella (Fab.) larvae were selected with fenvalerate and cypermethrin for 15 successive generations in the laboratory at 28(± 1)°C. The insect developed 7.8‐fold resistance to fenvalerate and no resistance to cypermethrin. The fenvalerate‐selected strain developed 2800‐fold and 1200‐fold cross‐resistance to endosulfan and carbaryl, respectively. This strain, however, did not manifest cross‐resistance to the organophosphorus insecticides, quinalphos, fenitrothion, monocrotophos and malathion, or to the synthetic pyrethroid, cypermethrin. The cypermethrin‐selected strain acquired 5‐, 4‐, and 3‐fold cross‐resistance to endosulfan, fenvalerate and carbaryl, respectively and no cross‐resistance to the above organophosphorus insecticides.