In vitro selection of Deltamethrin resistant strain of Trogoderma granarium and its susceptibility to Insecticides

Deltamethrin resistant strain of Trogoderma granarium was developed in the laboratory with field collected population from local market of Delhi as parental strain, through six successive generations by maintaining a selection pressure of 80% in each generation. The initial concentration of deltamethrin for selection pressure was increased from 0.0389 to 0.1076% in sixth generation. The increase in resistance based on LC₅₀ values, in each of ten successive generations were x 1.554, x2.217, x2.956, x3.092, x3,429 and x3.656. Cross resistant results showed that bifenthrin was not effective against deltamethrin resistant strain of T. granarium, malathion and dichlorvos showed good susceptibility.