Evaluating the effectiveness of weed biocontrol at the local scale

Abstract

Too many biocontrol programs have focused mainly on the establishment and prevalence of the biocontrol agents, with only limited studies on the impact of biocontrol at the individual plant level. Long-term effectiveness of biocontrol at the population level of the weed, and the resulting social and economic benefits are often not studied. The need for a comprehensive evaluation as an integral part of any biocontrol program, reasons for the limited emphasis on evaluation studies, and the potential role of community organizations in evaluation studies are discussed. Advantages and disadvantages of various valuation methods such as before and after release assessments, simulation experiments, relating damage levels to plant performance, and exclusion methods are compared. Evaluation methods commonly used in weed biocontrol programs in Australia are highlighted, along with an assessment on the success rates achieved. Evaluation protocols for aquatic and terrestrial weeds are suggested.