Biological control represents a very important tool in Integrated Pest Management programs. Mass rearing of natural enemies for field releases is one of the strategies proposed for the regulation of insect pest populations. Podisus nigrispinus Dallas (Heteroptera: Pentatomidae) is an important biological control agent of Alabama argillacea H¿bner (Lepidoptera: Noctuidae) in Brazil. However, the biological variables of this species as a function of abiotic factors should be further studied in order to optimize the integration of these organisms into Integrated Pest Management. Therefore, in this book we present aspects related to the effect of photoperiod on the biological variables of this very important predator.