Submitted to: Western Society of Weed Science Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 31, 2008
Publication Date: N/A
Technical Abstract: The first release of an introduced insect for classical biological control of invasive plants in the western U.S. occurred almost 50 years ago. Since then about 40 weed species have been targeted for biological control. Nine of these projects are mature enough to give us insights about why they succeeded and what limits effectiveness of the agents. Although these projects substantially reduced the target weed population over large areas, in some habitats they did not achieve satisfactory control. In some cases existence of resistant plant genotypes limited effectiveness of biological control agents. However, environmental conditions that either limited reproduction and/or survival of the agents or that favored growth of the target weed appear to be a common challenge. We can improve success by selecting agents that attack all known genotypes of the target weed, that are adapted to the various target habitats, and that are well defended against existing predators and parasites. Knowledge of the life history and environmental requirements of the biological control agents should help optimize integrated management strategies.