Forty-five field-collected strains of German cockroaches, Blattella germanica were tested for resistance to 12 different insecticides by the time-mortality response method in comparison with a known susceptible strain. Only low to moderate resistance to diazinon, chlorpyrifos, and acephate was detected. Resistance to malathion was widespread; about half of the strains tested showed high resistance. High resistance to the carbamates propoxur and bendiocarb also occurred. High resistance was uncommon with propoxur, but about 35 strains were highly resistant to bendiocarb. High resistance to pyrethrins was observed in about of the strains tested. Resistance to the pyrethroids allethrin, permethrin, phenothrin, fenvalerate, and cyfluthrin was detected in some of the strains examined. All of the strains tested were susceptible to one or more of the insecticides used. These results indicate that, although resistance is a serious problem in this species, satisfactory control should be possible by selection of an appropriate insecticide.

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Food and water consumption by adult female German cockroaches has been examined in relation to the reproductive cycle. Daily consumption was recorded for individual insects and was related to certain landmark events in each of four egg‐case production cycles. It was shown that peaks of feeding and drinking occur during the egg maturation period, but are abruptly terminated at the appearance of each egg case. During the period when females carry the egg case, they feed and drink sparingly. The possible role played by feeding and especially drinking in the regulation of reproduction in this important pest species is discussed. RÉSUMÉ Consommation d'eau et d'aliments pendant le cycle reproductif des femelles de Blattella germanica L'examen de la consommation d'eau et d'aliments par les femelles adultes de Blattella germanica a été lié au cycle reproductif. La consommation individuelle quotidienne des insectes a été reliée à certains événements marquants dans chacun de quatre cycles de production d'oothèque. Les pics d'alimentation et d'absorption se produisaient pendant la période de maturation des oeufs, mais disparaissaient brutalement à l'apparition de chaque oothèque. Pendant la période où les femelles portent les oothèques, elles s'alimentent et s'abreuvent parcimonieusement. Le rǒle éventuel joué par l'alimentation et particulièrement l'absorption dans la régulation de la reproduction de cet important insecte nuisible est examiné.

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Boric acid is a slow-acting, inorganic insecticide whose mode of action has not been satisfactorily elucidated. Reported here is evidence which shows that ingested boric acid destroys the cellular lining of the foregut of German cockroaches, Blattella germanica (L.). This effect appears to be sufficient to bring about the death of the insects, perhaps ultimately by starvation. This finding is important because resistance to conventional insecticides may re-establish boric acid as a prominent cockroach control chemical.