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Weed Research Site
Weed Research Site

Invasive non-native plants (weeds) jeopardize the health and sustainability of native forest and rangeland ecosystems and urban forests. Geographically separated from their co-evolved natural enemies, invasive plants are able to establish and rapidly proliferate in their new habitat.

Forest Service research focuses on developing tools and information needed by managers to predict, prevent, detect, monitor, control, and manage high priority invasive plants and restore and rehabilitate impacted landscapes. This research includes evaluating economic, social and environmental impacts; quantifying the biology, ecology, and interrelations among species and among tropic levels; developing biological controls; and elucidating the relationship between fire and invasive plants.

A large portion of the research focuses on biological control because it is one of the few tools proven effective in controlling widespread invasive plants.

Successful biological control agents can provide continuing and expanding control while reducing dependence on pesticides. However, because ecosystems are complex, it is important to consider the effects on all the other organisms within the community, not just the pest and biological control agent.

Invasive plant research at the Northern Research Station targets multiflora rose, Russian olive, oriental bittersweet, and honeysuckle in urban landscapes. Scientists focus on the interactions of invasive plants, soil chemistry, native herbivorous insects, and insect predators such as birds. See also:

The Rocky Mountain Research Station studies biological control of important rangeland weeds, such as leafy spurge, dalmatian toadflax, cheatgras, spotted knapweed and other invasive species:

Adult toadflax stem mining weevils
Adult toadflax stem mining weevils (Mecinus janthinus) established on yellow toadflax near Ovando, MT

Southern Research Station scientists are looking for biological control agents for Chinese privet, an important riparian weed. The station has also developed a field guide, Non-native Invasive Plants of Southern Forests.

The Pacific Southwest Research Station scientists are developing biological controls for some of the many invasive plant species present in Hawaii, such as strawberry guava.

The Pacific Southwest Research Station has published an overview of Invasive Plants in 21st Century Landscapes in the Pacific Northwest.