Hostname: page-component-78c5997874-fbnjt Total loading time: 0 Render date: 2024-11-13T08:47:49.731Z Has data issue: false hasContentIssue false

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 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Literature Cited

1. Dawson, J. H. 1978. Control of dodder (Cuscuta spp.) with pronamide. Weed Sci 26:660664.CrossRefGoogle Scholar
2. Kapusta, G. and Strieker, C. F. 1975. Selective control of downy brome in alfalfa. Weed Sci. 23:202206.CrossRefGoogle Scholar
3. Gysin, H. and Knusli, E. 1960. Chemistry and herbicidal properties of triazine derivatives. Adv. Pest Control Res. 3:289358.Google Scholar
4. Robinson, L. R., Williams, C. F., and Laws, W. D. 1978. Weed control in established alfalfa (Medicago sativa). Weed Sci. 26:3740.CrossRefGoogle Scholar
5. Waddington, J. 1980. Chemical control of dandelion (Taraxacum officinale) and perennial sowthistle (Sonchus arvensis) in alfalfa (Medicago sativa) grown for seed. Weed Sci. 28:164167.CrossRefGoogle Scholar
6. Weed Science Society of America. 1983. Herbicide Handbook. 5th ed., 515 pp.Google Scholar