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United States Department of Agriculture

Agricultural Research Service

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Research Project: BIOLOGICAL CONTROL OF SWALLOW-WORTS, INVASIVE WEEDS OF THE NORTHEASTERN UNITED STATES

Location: Biological Integrated Pest Management Unit

Project Number: 1907-22620-004-00
Project Type: Appropriated

Start Date: Dec 08, 2010
End Date: Dec 07, 2015

Objective:
1: Evaluate the risk posed by candidate biological control agents of swallow-worts. 2: Discover biological attributes of swallow-worts that contribute to their invasiveness and identify points of attack for enhancing biological control efficacy. 2a: Delineate the potential contributions of swallow-worts’ phytotoxic constituents to its invasiveness. 2b: Determine demographic rates for pale and black swallow-wort. 2c: Determine how swallow-wort responds to multiple seasons of repeated clipping/artificial defoliation. 3: Release and evaluate establishment and initial impact of biological control agents of swallow-worts. 3a: Document pre- and post-release densities of swallow-wort and assess changes in associated vegetation. 3b: Assess agent establishment.

Approach:
Foreign exploration will identify damaging natural enemies of swallow-worts in their native range. The fundamental host range of candidate biological control agents will be determined overseas and in quarantine. Swallow-wort tissue extracts will be assessed for allelopathic activity, a possible mechanism of invasion. Field-based plant demography studies will identify life stage transitions that strongly affect population growth rates of these invasive plants. Knowledge of these critical transitions will be used to guide the selection of potentially effective agents, a new approach for weed biological control in the U.S. Long-term defoliation/clipping studies will be conducted to document the rate of plant decline. Comparative surveys of areas infested and uninfested by pale swallow-wort will document its impact on plant density, cover and species richness of native ecosystems both before and after the release of approved biological control agents. Additional permanent monitoring sites will document changes in pale and black swallow-wort densities before and after release of agents. Establishment success of newly released agents will be evaluated.

Last Modified: 8/27/2014
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