Opportunities and constraints for the biological control of weeds in Europe

摘要

Although there has been increasing interest in Europe over the last few decades in trying to harness the potential of biological control as a management tool for weeds, securing funding for projects continues to be problematic whilst the successes have been limited. The incentives to use alternative technology are based on a number of interrelated factors, not least the dramatic rise in popularity of organic products (linked to increasing environmental awareness) and a powerful anti-GMO lobby. Combine this with new legislation to remove some chemical herbicides from the market or to restrict their usage, as well as soaring development costs for new products, and the opportunities for biological control have never been better. Here, we analyse the reasons for the limited uptake, and the challenges or constraints facing weed biocontrol from two different approaches: classical and inundative. For classical biological control against invasive alien weeds, Europe has lagged behind other continents (e.g.Australasia, North America) to the point that there have been no introductions thus far, whilst those that are in the pipeline still need to clear considerable legislative hurdles. These issues are highlighted for past and ongoing projects. For inundative biological control against indigenous or naturalized weeds—in this case, the use of products based on plant pathogens (bioherbicides)— the constraints are largely technological and commercial rather than bureaucratic: e.g. stability and efficacy; costs of production and registration; and limited markets. Opportunities to support the study and use of mycoherbicides, and strategies to overcome these constraints—improving production, formulation and application systems; genetic enhancement; synergistic mixtures of agents/metabolites —are discussed.