Management of Genetics of Biological-Control Introductions

For over 100 years, arthropod pests and weeds have been controlled by the introducion of exotic natural enemies (21). For almost as long, entomologists have discussed the importance of genetics and the possibility of genetic manipulations in biological control, and today these remain subjects of considerable debate. Perhaps the first issue raised was that predators and parasites might be artificially selected for improved performance in the field (46, 47, 59). In contrast, a major concern for laboratory rearing of insects and mites used in biological control is that such rearing will promote genetic adaptation to laboratory conditions and thus worsen performance in the field (57. 58). Another concern is that natural enemies imported for biological control constitute only a limited sample of the genetic variation present in the species, and may therefore lack the ability to adapt to their new environment (64,65). Many of these issues. and possible solutions. have been discussed recently