author(s)
Prabodh P Pate, VK Bhamare and Mohan K Narode

abstract
Resistance to insecticides was investigated by collecting field population of cotton jassid from different locations of Marathwada region of Maharashtra, India. All the field populations of cotton jassid differed in their resistance to insecticides. In general, Osmanabad population of cotton jassids registered developed 20.37-fold resistance to imidacloprid 30.5 per cent SC which was higher than other field populations of jassid. The resistance ratios varied greatly among the populations viz., imidacloprid 17.8 per cent SL (3.50- to 2.06-fold), imidacloprid 30.5 per cent SC (20.37- to 9.00-fold), imidacloprid 70 per cent WG (5.46- to 3.53-fold), acetamiprid 20 per cent SP (11.36- to 8.36-fold), thiamethoxam 25 per cent WG (3.11- to 1.80-fold) and clothianidin 50 per cent WDG (3.04- to 1.89-fold). High resistance factor of imidacloprid 30.5 per cent SC, acetamiprid 20 per cent SP and imidacloprid 70 per cent WG against all field populations of cotton jassid indicated development of resistance against these insecticides. Amongst the neonicotinoid insecticides tested, imidacloprid 17.8 per cent SL, clothianidin 50 per cent WDG and thiamethoxam 25 per cent WG were exhibited highly toxic to all the field populations of cotton jassid evidenced low resistance ratio.