Author
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JACOBS, JIM - NRCS |
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Mangold, Jane |
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Submitted to: USDA NRCS Technical Notes
Publication Type: Government Publication Publication Acceptance Date: 2/1/2007 Publication Date: 4/1/2007 Citation: Mangold, J.M., Jacobs, J. 2007. Ecology and management of perennial pepperweed [lepidium latifolium l.]. USDA NRCS Technical Notes-Montana-Invasive Species-MT-11. 8 p. Interpretive Summary: Perennial pepperweed, also called tall whitetop and often confused with whitetop (Cardaria draba), is a rhizomatous perennial weed threatening riparian areas, irrigation ditches, and floodplain meadows. This weed in the mustard family (Brassicaceae) spreads by creeping roots and rhizomes, and prolific seed production. Found most often in seasonally flooded areas, perennial pepperweed can also spread to upland and rangeland sites where it can form dense patches that compete with crops, forage plants, and riparian plants. Infestations reduce crop yield and livestock carrying capacity while increasing production costs. Native to southeastern Europe and western Asia, pepperweed was first found in Montana in Gallatin County in 1935. By 2002 it had been reported from 17 counties with a total of 2,750 acres infested. In Montana it has been found along roadways, railroads, the Missouri River, irrigation ditches, in winter wheat, alfalfa, Conservation Reserve Program, pastures, on dry hillsides, and in rangeland. Perennial pepperweed is ranked as a Category 2 noxious weed in Montana, meaning it is currently present and believed to be rapidly spreading from existing infestations. Perennial pepperweed can be temporarily suppressed using herbicides that contain metsulfuron, chlorsulfuron, or imazapic as active ingredients. Long-term herbicidal control requires repeated applications. Cattle, sheep, and goats will graze perennial pepperweed, but the effects on population fitness of long-term grazing with these animals are not known. Mowing and sheep grazing reduce stand density for up to one year. There are no approved biological control insects for release on perennial pepperweed. Technical Abstract: Perennial pepperweed, also called tall whitetop and often confused with whitetop (Cardaria draba), is a rhizomatous perennial weed threatening riparian areas, irrigation ditches, and floodplain meadows in Montana. This weed in the mustard family (Brassicaceae) spreads by creeping roots and rhizomes, and prolific seed production. Found most often in seasonally flooded areas, perennial pepperweed can also spread to upland and rangeland sites, and it is adapted to salt-affected soils. It can form dense patches that compete with crops, forage plants, and riparian plants. Infestations reduce crop yield and increase production costs, reduce livestock carrying capacity, and its control is costly. Perennial pepperweed is native to southeastern Europe and western Asia. The first record of perennial pepperweed in Montana is from Gallatin County in 1935 along a roadside near Manhattan. By 2002 it had been reported from 17 counties with a total of 2,750 acres infested. In Montana it has been found along roadways, railroads, the Missouri River, irrigation ditches, in winter wheat, alfalfa, Conservation Reserve Program, pastures, on dry hillsides, and in rangeland. Perennial pepperweed is ranked as a Category 2 noxious weed in Montana, meaning it is currently present and believed to be rapidly spreading from existing infestations. Perennial pepperweed can be temporarily suppressed using herbicides that contain metsulfuron, chlorsulfuron, or imazapic as active ingredients. Long-term herbicidal control requires repeated applications. Cattle, sheep, and goats will graze perennial pepperweed, but the effects on population fitness of long-term grazing with these animals are not known. Mowing and sheep grazing reduce stand density for up to one year. There are no approved biological control insects for release on perennial pepperweed. |
