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Research Project: Biological Control in Integrated Weed Management of Invasive Weeds from Europe, Asia, and Africa

Location: European Biological Control Laboratory

Project Number: 0212-22000-031-000-D
Project Type: In-House Appropriated

Start Date: Dec 2, 2020
End Date: Dec 1, 2025

Objective 1: Explore for natural enemies, primarily arthropods, of invasive weeds identified as high priority targets by the ARS Office of National Programs, performing collections, importations and exportations in compliance with local and international regulations. High priority pests include Sahara mustard, French broom, annual grasses, stinkwort, tree of heaven and swallow-worts. Objective 2: Perform taxonomic, population genetic, and phylogeographic studies of target weeds and biological control agents to better understand the origin of invasive populations, arthropod-plant relationships, and clarify species. • Sub-objective 2A Phylogeography of Sahara mustard, stinkwort, ventenata. • Sub-objective 2B Genetic characterization of potential biocontrol agents. Objective 3: Identify the biological, physical and chemical parameters that affect the efficacy, specificity, and safety of biological control agents, and those underlying the interactions between target weeds, biological control agents, and the environment. • Sub-objective 3A Assess the potential host specificity on selected plant species, focusing on host use of candidate agents for tree of heaven, stinkwort, swallow-worts, medusahead and Sahara mustard. • Sub-objective 3B Investigate foraging behavior and impact of biological control agents with French broom weevil and French broom psyllid. • Sub-objective 3C Investigate safety procedures of biological control agents, including French broom arthropod candidates and other potential biological control agents. • Sub-objective 3D Compare the impact of rhizospheric bacteria and fungi from native and invasive ranges on the fitness of the annual grass weed ventenata.

The goal of this current 5-year plan is to conduct a customer-driven research program that will enhance our ability to manage invasive weeds in the U.S. Successful alien weeds usually lack natural enemies, which control them in their native ranges. The European Biological Control Laboratory research team and associated cooperators will accomplish this by using a combination of hypothesis and goal-driven research toward the discovery and development of exotic natural enemies for classical (=importation) biological control of alien weeds in the U.S. The long-term research plan will lead to environmentally safe and sustainable management of weeds that threaten U.S. agriculture and natural ecosystems over large areas. The process usually involves three phases that can be conducted in parallel: 1) exploration to discover and characterize candidate arthropod biological control agents and their target host plants in full compliance with current regulations in host countries regarding exportation of live organisms and benefit-sharing, 2) morphological and genetic characterization of the field collected arthropod material and related natural enemies, and 3) evaluation of the host specificity and effectiveness of the best selected candidate biological control agents. Candidates that are found to be safe and effective are then proposed for release in the U.S., and must undergo a rigorous review and permitting process involving state and federal agencies. Research on Sahara mustard, French broom, annual grasses, tree of heaven and swallow-worts will continue, and additional weeds will be targeted in response to stakeholder demand and available resources. EBCL plays a key role providing research and prospective agents to federal and state cooperators necessary for the successful control of target weeds. The research proposed in classical biological control is highly cost effective, and critical to achieving ecologically rational, sustainable management of some of the most important invasive weeds in the United States.