Using examples from surveys to collect natural enemies of the indigenous African sugarcane borer Eldana saccharina Walker throughout Africa, insight is given into what factors should be investigated should biological control of other indigenous African stemborers be considered. Indigenous host plant range, parts of indigenous and crop hosts attacked, types of natural enemies found in these different niches and natural enemy attack strategies are all important factors to consider when planning redistribution of indigenous natural enemies from one part of Africa to another. This knowledge is important when choosing the correct natural enemy for mass rearing and release into the affected crop, and can be used to manage the crop habitat, using the indigenous tritrophic systems identified, to increase crop diversity and thus effectiveness of indigenous natural enemies.

Based on an extensive literature search, the present overview discusses the economic relevant diseases of Siluroidei, cultured for human consumption. One herpes virus and two irido viruses play a significant role for channel catfish (Ictalurus punctatus), sheatfish (Silurus glanis ) and yellow bullhead (1. melas )culture, respectively. There is only one fish species-specific bacterial disease which has an economic impact in the catfish industry: Edwardsiella ictaluri. Secondary infections with opportunistic bacteria and fungi are of interest in all catfish species cultured both under intensive and extensive circumstances. Etiology, pathology, prevention and treatment are shortly discussed for all diseases. Also some diseases of unknown etiology, which occur in African (Clarias gariepinus ) and Asian (C. batrachus ) catfish, are described.