Susceptibility of different strains of German cockroach, (B.germanica) to three insecticides in hospitals affiliated to Kerman university of medical sciences

Background and The susceptibility of three wild strains of B.germanica collected from different hospitals (Shafa, Kerman darman and Shahid bahonar) affiliated to Kerman university of medical sciences were evaluated using Pirimiphos methyl, Propoxur and Lambadacyhalothrin. The method of testing was followed according to method of WHÔ, through contact procedure. The relationship between mortality and concentration was plotted. The LD50 and LD90 values were measured by probit analysis. Findings indicated that in comparison with the sensitive strain with LD50 values of 0.42, 48.47 and 115.42 for lambbacyholathrin, propoxur and pirimiphos methyl respectively. Shafa strain with LD50 values of 1, 56.71 and 88.82 and with the resistance ratio of 2.38, 1.17 and 0.77 fold were resistant to lambdacyholothrin and sensitive to propoxur and pirimiphos methyl, respectively. Kerman darman strains with LD50 values of 0.60, 54.20 and 86.38 and resistance ratio of 1.42, 1.12 and 0.75 fold respectively were sensitive to all three insecticides. Çonclusion: The LD50 values of three wild strains were lower than the LD50 value of the susceptible strains. This result showed that all of the wild strains were negative cross resistance to Pirimiphos methyl.