Seven years of post-release monitoring for biological control agents released for biological control in the Netherlands: impact of regulatory measures on establishment and use

Abstract: In The Netherlands since 2005, rules are in place that regulate the release of a natural enemy as an invertebrate biological control agent (IBCA). Prior to an application for release of a BCA, the Plant Protection Service evaluates the potential risks of such a release for the native flora and fauna, in a so called Environmental Risk Analysis (ERA). When a licence is permitted for a natural enemy, it can be released for a period of maximum five years. Since 2004, 22 BCA species have been released, based on such an ERA. During that same period we established several surveys for different groups of natural enemies in the natural environment to verify whether they escape from the greenhouse, and whether they have established outdoors. We found that several of the IBCAs – predatory mites (Phytoseiidae), predatory bugs (Anthocoridae, Miridae), parasitoids (Braconidae), coccinellids (Harmonia axyridis) – disperse from (greenhouse) cultures into the natural environment and some of these have established outdoors. In this paper an account is given on the methods and results of seven years surveys of different groups of natural enemies and the potential impact of such releases on the native fauna and the use of biological control.