Cryptolaemus montrouzieri (Mulsant) (Coccinellidae: Scymninae): a review of biology, ecology, and use in biological control with particular reference to potential impact on non-target organisms

Over the years, Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae) has been used in both classical and augmentative biological control programmes. The ladybird is also considered important in certain conservation biological control programmes. This paper provides a critical review of the literature pertaining to its biology, ecology and use, with a particular emphasis on potential impact on non-target organisms. C. montrouzieri has many of the attributes of an effective natural enemy, including a rapid development rate, high reproductive potential, good adaptation to a range of tropical and subtropical climates, high prey consumption rates by both adults and larvae and ease of rearing. The coccinellid has been introduced into at least 64 countries/territories to control more than 16 pest species. C. montrouzieri is a polyphagous predator that exploits hosts in at least eight hemipteran families. It is noteworthy that it has adapted to feed on new insect families in some new localities where it has been introduced. Although the wide host range has allowed its use against a variety of pest species, it is also a good indicator of the potential to feed on non-target species. In view of the continued interest to utilize the predator in new non-native localities, questions have arisen regarding its potential to cause negative impacts, especially against non-target organisms. Given the wide recorded host range, it seems unnecessary to conduct additional host range tests as significant decisions can be made based on the available information. Thus, when the available data are interpreted based on a centrifugal process, it is apparent that the ladybird has a potentially very broad host range. Therefore, even without additional studies, it would be reasonable to assume that the ladybird has the potential to extend its host range in unpredictable ways. Clearly, the beetle would provide a good model for conducting post-release studies, especially where the predator has been established for a long time. Such studies would not only provide insight into the impact of introducing generalist non-native coccinellid predators but also help to increase our understanding of the mechanisms limiting host range.