CORVALLIS - The spread of noxious, exotic (non-native) weeds in Oregon costs the state millions of dollars annually in lost economic productivity and resources spent on weed control programs. Researchers at Oregon State University hope to enlist the help of landowners and land managers throughout the state in the war on weeds via an online-based weed information exchange called Weedmapper.

"The idea behind Weedmapper is to provide agency officials, land managers and Oregon landowners with quick and easy access to the latest information available on the location and extent of noxious weed infestations around the state," said Doug Johnson, a rangeland ecologist in the OSU Department of Rangeland Resources, and leader of the Weedmapper project.

"In addition, Weedmapper is designed to help more people get involved in the weed control effort," Johnson added. "The site invites any Oregon landowner with Internet access to report sightings of exotic weeds."

The recently completed website was developed at OSU by a team of range scientists and web information technologists, many of whom are OSU graduate students. The Rogue River National Forest, Oregon Department of Agriculture, U.S. Department of Agriculture and Bureau of Land Management cooperated with the OSU Rangeland Resources Department in the design and construction of Weedmapper. See it online at

Weedy invaders such as Russian knapweed, scotch thistle, gorse and tansy ragwort cause harm by displacing native plants on forest and rangelands, damaging wildlife habitat and grazing areas for livestock. In addition, some weeds such as tansy are toxic to livestock.

The more widespread invasive noxious weeds become, the greater the damage they cause. For example, tansy ragwort, which is poisonous to livestock, is estimated to have caused economic losses of $5 million annually in Oregon for many years until weed control strategies began to reverse the spread of tansy in the late 1990s.

The noxious weed database within the Weedmapper web site includes photographs and descriptions of weeds as well as maps showing the extent of known infestations. The maps are viewable at the state, county, township or section (square mile) level.

Weedmapper also includes risk assessment tools to help users understand the potential scale of noxious weed infestations in Oregon, and links to other sources of information on weed management and control. However, one of the most valuable components of the website may be the noxious weed sighting report feature.

"The weed report form incorporated into the Weedmapper web site was developed by the Oregon Department of Agriculture weed control program," said Johnson. "Reports submitted via the website go directly to the ODA and are independently verified before the information is added to the statewide noxious weed database. The mapping feature of the website allows reporters to indicate the specific position of a noxious weed sighting in degrees of latitude and longitude.

"Our hope is that the reporting tool in Weedmapper will generate citizen involvement in statewide control efforts," said Johnson.

Tim Butler, manager of the Oregon Department of Agriculture's Noxious Weed Control Program, also hopes Weedmapper will make a difference in Oregon's war on weeds. Early detection is the key to controlling the spread of noxious weeds, Butler said.

With the large numbers of people and products moving in and out of Oregon, it's difficult to keep noxious weeds out of the state, he added.

"For many years we maintained a weed database based on annual weed sighting reports from state and federal land managers and county weed supervisors," said Butler. "With the introduction of Weedmapper, gathering and sharing information about noxious weed infestations can be done more quickly and effectively and more Oregonians can get involved in helping track noxious weeds."

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Doug Johnson, 541-737-1624