[Genetic control of Blattella germanica]

Based on a literature survey, the possibilities of a genetic control of the German cockroach (Blattella germanica) are shown. First, an oversight is given on the cytogenetics of the German cockroach, including some important mutations. Then the control methods by genetic mechanisms are explained. This chapter begins with analysing the relevant biological pecularities. In control measures, the dominant lethal mutations (induced by rays rich with energy and by chemosterilants) have only a chance if they can be applied in the scope of autosterilization of natural populations. Reciprocal translocations may expect maximum consideration in the future of the control of the German cockroach. Some of these are already available in the heterozygote state. But the establishment of homozygous strains was not yet successful up to now. The possibilities of the application of translocation-heterozygotes are discussed. Such mutant strains of cockroaches which bear several translocations in the heterozygous state, offer the most promising way of control. This may even include the population's eradication. A long-lasting regulation of the population may be achieved with the introduction of insects mutated in this manner even in the case if a complete eradication is not attainable. It might be expected that also other genetic mechanisms may contribute, in future, to the improvement of cockroach control. Such mechanisms may be conditional lethal factors, sex distortions, and others more.