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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGY AND MANAGEMENT OF INVASIVE WEEDS IN THE WESTERN UNITED STATES Project Number: 5325-22000-020-00
Project Type: Appropriated

Start Date: Jun 15, 2005
End Date: Jun 14, 2010

Objective:
1) Conduct population- and organismal-level studies on invasive weeds, measure their impact on agricultural and natural environments, and conduct research on their growth, distribution and control. 2) Identify, collect, and evaluate natural enemies for management of invasive weeds, and to develop and apply new benefit/ risk evaluation methods for biological control of weed activities. 3) Conduct ecological, community, and area-wide assessments of invasive species impact; develop and implement biological control release and evaluation technologies; conduct natural enemy impact assessments, and integrate biological control programs with other weed control methods. 4) Assess post-release recovery of desired species; and develop and integrate effective revegetation technologies with biological control technologies, with overall focus on Integrated Vegetation Management methodologies.

Approach:
1) Permanent quadrats will be established at sites in Turkey to monitor seasonal changes in plant density, plant phenology and seed production of yellow starthistle, and will be compared to similar data collected in California. Differences in life table parameters will indicate what general differences in survivorship and fecundity occur. Such studies will include detailed plant growth and life-table experiments conducted on the target plants under a range of moisture, nutrient, and soil conditions that represent typical growing condition in portions of CA. 2) Foreign surveys for natural enemies are planned in the native homes of four weeds proposed as targets for this project. Foreign surveys will be composed of two types of investigations- short, opportunistic trips, and intensive surveys in selected regions. While short visits are cheaper, and are necessary to select areas for more intensive effort, we will favor more intensive surveys that will result in a prioritized list of potential biocontrol agents. Additionally, we will assess the risk to non-targets by potential biological control agents through host range tests to demonstrate the host specificity of the candidate agent. Additionally, we will also assess the probable impact of new biological control agents on the perspective target and their developmental biology. 3) We plan to investigate different aspects of community and area-wide interactions of pest plants and natural enemies using a variety of methods. In herbivory studies, we plan to conduct three different types of research, controlled greenhouse studies where different treatment densities of the biological control agents are held on fixed sized plants; field studies where fixed levels of insects are associated with naturally growing plants under cage conditions; and open field plants that will have manipulated densities of natural enemies that will more precisely mimic the phenology and density of expected attack. These studies will measure factors such as defoliation levels, water loss, plant regrowth, root reserves, seed production, etc., and will allow evaluation of host and natural enemy synchrony under realistic field conditions. 4) A combination of detailed intensive population dynamics studies and more extensive generational sampling will be conducted for the saltcedar leafbeetles in multiple release sites, and mapped through a combination of remote sensing and GIS technology. As beetle populations spread, the area and target plants affected by the defoliation will be further characterized and the number of plants sampled will be enlarged to fill the space inhabited by the expansion of the beetle populations. Both aerial remote sensing and hyperspectral imaging will be conducted using ARS and NASA equipment with summary maps made available to cooperators through internet services. FY06 Program Increase. Add 1 SY at a later date.

Last Modified: 11/28/2014
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