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United States Department of Agriculture

Agricultural Research Service

Research Project: Biological Control of Invasive Terrestrial and Riparian Weeds in the Far Western U.S. Region, with Emphasis on Thistles, Brooms and Cape-Ivy

Location: Exotic and Invasive Weeds Research

Project Number: 5325-22000-025-00
Project Type: Appropriated

Start Date: Jun 15, 2010
End Date: Jun 14, 2015

Objective:
1) Characterize the diversity and basic biology of target weeds, including yellow starthistle and other weeds such as Russian thistle and Cape-ivy, estimate their potential range and environmental/economic impacts, and determine their regions of origin. 2) Discover and evaluate the host-specificity and potential efficacy of arthropod biological control agents for target weeds such as Cape-ivy, yellow starthistle, Russian thistle, French broom, and Scotch and bull thistles. 3) Evaluate the population dynamics and efficacy of biological control agents, their impact on non-target species, and relevant interactions in associated biological communities and farming systems, for weeds such as Cape-ivy, French broom, yellow starthistle, and Russian, Scotch and bull thistles.

Approach:
We will develop classical biological control programs to help control invasive alien plants such as Cape-ivy, yellow starthistle, Russian thistle, French broom, and Scotch thistle. Molecular genetic methods will be used to help characterize genetic diversity of the target weeds and determine their geographic origin, which are necessary to direct foreign exploration for prospective agents. Climatological analysis of the known geographic distribution of target weeds will predict potential geographic range for invasion in the USA. Field and laboratory experiments will be used to measure the environmental and economic impacts of these target weeds. With the assistance of foreign cooperators, we will discover prospective arthropod biological control agents for the above weed targets. We will evaluate the host-specificity and potential efficacy of these agents in experiments conducted in our quarantine laboratory and in the field where these agents are native. Host specificity bioassays and GC-MS analysis of volatile organic chemicals of target and nontarget plants will help determine the importance of plant secondary chemistry in determining specificity of prospective biological control agents. We will conduct field experiments to study the population dynamics and efficacy of biological control agents after they have been released for weeds such as Cape-ivy, French broom, yellow starthistle, and Russian, Scotch and bull thistles. This will include studies on impact on non-target species, and on possible interactions within targeted biological communities and farming systems.

Last Modified: 7/28/2014
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