Determination of Cross- Resistance and Multiple Resistance in Cryptolestes ferrugineus (Stephens) Madhumathi T, Subbaratnam GV* Department of Entomology, Agricultural College, Bapatla-522101 * Department of Entomology, College of Agriculture, Rajendranagar, Hyderabad-500030 Online published on 15 October, 2011. Abstract Malathion, dichlorvos and phosphine resistant Machilipatnam strain of C. ferrugineus hah dedeloped cross-resistance to fenitrothion, profenofos (47.0 and 3.7 folds at LC99.9) and multiple resistance to carbaryl and deltamethrin (6.8 and 4.8 fold at LC99.9) in comparison with susceptible or less resistant Charlapalli strain. Synergism due to PBO was found in malathion (SF 7.08), dichlorvos (SF 1.93), profenofos (SF 1.64) and deltamethrin (SF 5.04) at LC99.9 level. Except in the case of deltamethrin, the synergistic factors were less than the corresponding resistance factors revealing the possibility of some other mechanisms of resistance in addition to the detoxification mechanism by MFO. Top Key words Cryptolestes ferrugineus, malathion, dichlorvos, phosphine, fenitrothion, profenofos, endosulfan, cross-resistance, multiple resistance. Top |