Insecticide-resistance in bed-bugs

A simple method of measuring insecticide-resistance in bed-bugs is described. Batches of adult bugs are put on small pieces of filter-paper impregnated with oil solutions of insecticides, and mortality is estimated after 5 days at 25 degrees C.In both Cimex lectularius and C. hemipterus, two kinds of resistance can develop, either independently or in conjunction. One involves DDT, methoxychlor and analogues; it cannot be overcome by the addition of DMC. The other involves gamma-BHC, dieldrin and various other chlorinated cyclodiene insecticides. The resistance spectrum of bed-bugs towards this group of compounds resembles those of Anopheles gambiae and Musca domestica, indicating similarity in the defence mechanism.