[Effect of permethrin selection on the developmental cycle and fertility of cockroaches (Blattella germanica)].

Each generation of Blattella germanica were treated with a dose of 0.42 microgram permethrin per VI instar larva. The fecundity varied from 8.21 to 33.66 for I instar larvae per female. Reproduction was significantly lower than that evaluated for untreated insects in third and fourth generations, but significantly higher in the fifth generation. Mortality among insects treated with permethrin, with the exception of the fourth generation only, was higher than among untreated cockroaches. In the third, fourth and fifth generations, the biotic potential was significantly lower in groups of treated insects than in untreated ones. The length of the developmental period of B. germanica treated with permethrin, measured during 7 generations, showed no significant changes in comparison with the control groups.