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Herbicidal Control of Duncecap Larkspur (Delphinium occidentale)

Published online by Cambridge University Press:  12 June 2017

Larry V. Mickelsen
Affiliation:
USDA, Agric. Res. Serv., U.S. Dep. Agric. Poisonous Plant Res. Lab., 1150 E. 1400 N. Logan, UT 84321
Michael H. Ralphs
Affiliation:
USDA, Agric. Res. Serv., U.S. Dep. Agric. Poisonous Plant Res. Lab., 1150 E. 1400 N. Logan, UT 84321
David L. Turner
Affiliation:
Math. and Stat., Utah State Univ., Logan, UT 84322
John O. Evans
Affiliation:
Plant Sci., Utah State Univ., Logan, UT 84322
Steven A. Dewey
Affiliation:
Plant Sci., Utah State Univ., Logan, UT 84322

Abstract

Several herbicides were evaluated for their ability to control duncecap larkspur, a serious poisonous plant on mountain rangelands in the western U.S. Duncecap larkspur density was reduced from 33 to 93% by triclopyr applied at 2.2, 4.5, and 9.0 kg ae/ha. Picloram applied at 2.2 and 4.5 kg ae/ha reduced density from 33 to 99%. Metsulfuron applied at 86 and 138 g ai/ha reduced density from 50 to 98%. Glyphosate was the most effective herbicide, reducing density by 90 to 100% when applied at 2.2 kg ai/ha. Glyphosate reduced the cover of grasses and perennial forbs but increased cover of annual forbs. All rates of picloram and metsulfuron reduced forb cover. Grass cover increased in most plots where duncecap larkspur and forbs were reduced.

Type
Weed Control and Herbicide Technology
Copyright
Copyright © 1990 by the Weed Science Society of America 

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References

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