To meet the overarching goal of this proposal, the development and implementation of an ecologically sound and sustainable approach to the long-term management of destructive invasive plant species, we have developed three primary tasks. Each of these tasks will be elaborated in this section in detail and then tied together to meet the overall goal of developing a systematic and holistic approach to this investigation. This overall project, however, is based on the assumption that biologically-based control can provide one of the core technologies for controlling many invasive species, especially when linked with other effective management strategies in an integrated program. A detailed rationale for this perspective has been developed for saltcedar (DeLoach et al. 2000, Dudley, et al. 2000), and others have provided similar rationales for biological control of weeds in general (see McFadyen 1998). Our approach also assumes that biological control can be used in a safe and effective manner and we have proposed to help develop and test new methods that can be effectively used to assess the degree of risk and benefit that may be involved in using biologically-based technologies. Both of these program elements are based on the need for sound biological data collected on multiple levels of consideration, from the genetic/ molecular to the community/ ecological end of the spectrum.

We have selected three specific target plants (Tamarix spp, Arundo donax, and Centaurea solstitialis) for our investigations as they are economically important to a number of USDA stakeholders and are critical to the environment as they are known to harm a several desirable native species. We also selected these three target plants as they all are being considered as targets for major multi-agency biological control programs and thus will provide excellent test cases for risk/ benefit evaluations under Task 1. Since the risk/benefit analysis is certain to generate additional data needs, this information can be provided by investigations conducted through Task 2 (detailed experimental studies on the target systems) and Task 3 (biocontrol test implementation and monitoring). In addition, the risk/ benefits analysis effort is planned to draw upon other interesting historical biological control project areas where adequate supporting data already exists or could be collected with little additional effort. If practical, other programs such as the Musk Thistle/ Rhinocyllus conicus example may be evaluated through cooperators and with existing data.