Study on the Cross-Resistance of Permethrin-Resistant German Cockroach to Insecticide

Objective The cross resistance of permethrin-resistant strain of Blattella germanica to deltamethrin,cypermethrin and propoxur was studied.Methods The method of contacting with chemical cover in jar was used in this study.Results The cross-resistant ratioes of permethrin-resistant strain with the above three kinds of insecticides were 2.40- 4.14, 1.83- 4.78 and 1.16- 1.69 respectively,whose resistant ratio was 5.89- 8.02 and the death ratio was 85%-100% percent.The 4th generation of resistant strain had cross-resistance to pyrethroid,while the 6th had stronger.But the resistant-strain had no resistance to propoxur.Conclusion One kind of insecticide being keeped using is easy to make resistance and cross resistance.