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# Difficulty in Controlling Duncecap Larkspur (Delphinium occidentale)

Michael H. Ralphs and David L. Turner
Weed Technology
Vol. 3, No. 2 (Apr. - Jun., 1989), pp. 335-339
Stable URL: http://www.jstor.org/stable/3986945
Page Count: 5
Duncecap larkspur was not killed by triclopyr, picloram, or clopyralid applied once at recommended rates. Triclopyr at 1.1, 1.7, 2.2, and 4.6 kg ae/ha applied twice to the same plots in two consecutive years reduced duncecap larkspur density from 29 to 64%. However, the higher rates of triclopyr left 2 $\text{plants}/{\rm m}^{2}$, an unacceptable level for preventing cattle poisoning.