Insect biological control and non-target effects: a European perspective

A 4-year research project on 'Evaluating Environmental Risks of Biocontrol Introductions in Europe' (ERBIC) is described, and early results are presented. The project focuses on arthropod biological control (using both microbial and macrobial agents), and uses literature review, case studies with empirical work and various types of modelling to illuminate risk to non-target organisms. These methods will hopefully lead to the development of usable methodologies and guidelines for risk assessment in arthropod biological control, by the project's completion in 2002. Reviewing existing published and unpublished data on the classical biological control of insects (a first step in this project) has revealed that for only 1.5% of introductions is there some data regarding the realized field specificity of the agent. For a tiny proportion of introductions there are quantitative data regarding mortality in non-targets. From these cases, with some extrapolation, we can deduce that 10% or less of classical biological control introductions in the past led to population changes in non-targets. Data on population-level effects from simulated uses or trials suggest that 49% of inundative or augmentative uses of agents led to (local, short-term) population changes for non-targets. Case studies into: (i) exotic specialist parasitoids used in the greenhouse; (ii) exotic generalist parasitoids used inundatively in the field; (iii) exotic generalist predators used inundatively; and (iv) fungi and nematodes used as bioinsecticides, are outlined. The results so far demonstrate: (i) the apparent safety of Trichogramma (generalist parasitoid) releases in Switzerland, despite rare species within its host range; (ii) the lack of overwintering capability in northern Italy in one generalist predator (Orius insidiosis), but its presence in another (Harmonia axyridis); (iii) little evidence that the predation of certain stages of native predators by introduced predators will enhance environmental risks in the cases in question; and (iv) the apparent safety of bioinsecticide releases of particular pathogen strains for important naturally occurring predators when exposed directly or by feeding on infected prey.