Mark Schwarzlander
Friday, October 17, 2008 - 9:30-10:00
The main focus of the host range testing process is to assess the environmental safety of a candidate biological control agent based upon which an agent may or may not be introduced and released in North America. This process was developed and refined to exclude any adverse effect the release of an exotic biological control agent could pose to indigenous species or ecosystems. Historically, the rate of biological weed control programs with documented nontarget effects has been very low. Nonetheless, there are biological control agents that cause non-target effects, either directly by feeding on indigenous plants or competing with indigenous herbivorous arthropods, or indirectly as prey for indigenous predators with cascading consequences to ecosystems. Some of these agents were introduced in the 1960s, at a time when socio-political and environmental priorities were different in the U.S., others were introduced into neighboring countries and immigrated over time into the U.S. or were inadvertently introduced, while other species only cause negligible effects, which were predicted in pre-release host range tests. In addition, there are cases where biological control agents caused indirect effects that were not predictable and/or are controversially evaluated. In this presentation I will review non-target effects of biological weed control agents in the U.S. along with the potential or known impact these effects may have on native flora and fauna. I will argue that comprehensive pre-release host range testing provides a sufficiently reliable process to predict the environmental safety of a biological control agent.
Keywords: HOST RANGE TESTING, BIOLOGICAL CONTROL, NON-TARGET EFFECTS