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Controlling Weeds in Dormant and Nondormant Alfalfa (Medicago sativa)

Published online by Cambridge University Press:  12 June 2017

Elroy J. Peters
Affiliation:
U.S. Dep. of Agric., Agric. Res. Serv., Columbia, MO 65211
Robert A. McKelvey
Affiliation:
U.S. Dep. of Agric., Agric. Res. Serv., Columbia, MO 65211
Richard Mattas
Affiliation:
Dep. Agron., Univ. of Missouri, Columbia, MO 65211

Abstract

When applied in early February, simazine [2-chloro-4,6-bis(ethylamino)-s-triazine], pronamide [3,5-dichloro-(N-1,1-dimethyl-2-propynyl)benzamide], secbumeton [N-ethyl-6-methoxy-N′-(1-methylpropyl)-1,3,5-triazine-2,4-diamine], and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] effectively removed weedy Bromus species from established alfalfa (Medicago sativa L.) and increased yields of alfalfa forage. Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], terbacil (3-tert-butyl-5-chloro-6-methyluracil), and hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine- 2,4(1H,3H)-dione] had no adverse effects on yields of alfalfa when applied in late March. Paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) was somewhat less effective for controlling weeds when applied in late March than when applied in February. When applied to weed-free stands of alfalfa after dormancy was broken, metribuzin, terbacil, hexazinone, and simazine, but not pronamide, significantly reduced yields of alfalfa. Terbacil applied immediately after the first cutting did not significantly reduce yields of the second cutting. Terbacil and bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] applied when alfalfa had 5 cm of regrowth significantly reduced yields.

Type
Weed Control and Herbicide Technology
Copyright
Copyright © 1984 by the Weed Science Society of America 

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References

Literature Cited

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