Relative toxicity of certain insecticide against the field population of spiralling whitefly, Aleurodicus disperses Russell and its management

Adults of spiralling whitefly, Aleurodicus disperses (Hemiptera: Aleyrodidae) were collected from three different locations viz, field with no pesticide application (location I), field where insecticides were applied and control failure were also observed (location II) and field where insecticides were applied but with no known reports of control failure (location III). Three insecticides quinalphos 25% EC @ 250 g a.i ha⁻¹, fenvalerate 20% EC @ 25 g a.i ha⁻¹ and imidacloprid 17.8% SL @ 20 g a.i ha⁻¹at seven different concentrations were selected to test the resistance/ susceptibility of the populations. Population collected from location-II showed resistance with resistance ratio of 2.60, 2.90 and 1.85 and population from location-III showed resistant ratio of 1.14, 1.62 and 1.28 against quinalphos, fenvalerate and imidacloprid respectively. The resistant population was effectively managed by new generation insecticides, thiamethoxam 12.6% + lambda cyhalothrin 9.5% ZC @ 33+ 15.75 g a.i ha⁻¹, clothianidin 50% WDG @ 20 g a.i ha⁻¹ and flonicamid 50% WG @ 75 g a.i ha⁻¹at laboratory experiments. Higher mortality of whitefly was observed with thiamethoxam 12.6% +lambda cyhalothrin 9.5% ZC @ 33+15.75 g a.i ha⁻¹ under field conditions.