Insecticide Resistance Pattern in the Selected Strains of Brown Planthopper Nilaparvata Lugens Stal in Rice

Insecticide resistance in different strains of rice brown planthopper Nilaparvata lugens (Stal) was undertaken in the laboratory and green house conditions at Directorate of Rice Research, Hyderabad. The resistance ratios between Godavari strain (field population) and susceptible strain were in the decreasing order for BPMC, chlorpyriphos, phosphamidon, phorate, carbaryl, monocrotophos, carbofuran and quinalphos. Monocrotophos strain exhibited slight resistance to monocrotophos, moderate cross resistance to BPMC and carbaryl, and negligible cross resistance to other insecticides. Neem gold₄ strain showed considerable resistance to neem formulation Neem gold₄, cross resistance to carbaryl and BPMC, slight or no cross resistance to other insecticides.