Yuma County Office
2200 W. 28^th Street, Ste. 102
Yuma, AZ 85364
(928) 726-3904
(928) 726-8472 FAX

Production Update:

Insect Management: Spider mites (picture, 71KB) are not common in alfalfa grown for hay and serious damage is often associated with water stress. When infested fields are watered, the problem often clears up in a matter of days. In recent years, spider mites have been more common in alfalfa hay fields during the spring/summer months. Spider mites infestations are usually confined to the lower leaves. They feed by inserting long needle-like mouth parts into leaves removing plant sap. Leaves become stippled with chlorotic spots. Infested leaves are covered with webbing and turn yellow. With severe feeding, leaves turn brown from necrosis and desiccation causing defoliation. Damage starts in the lower plant canopy moving upward. Feeding damage can reduce yield, quality and retard growth. Definitive monitoring and treatment guidelines have not been developed for spider mites in alfalfa grown for hay.

Weed Control: The time has passed when the contact herbicides, Gramoxone and Buctril, can be safely and effectively used in alfalfa. Hot, dry conditions, rapid crop regrowth, and preharvest intervals make it difficult to safely and effectively use these products between March and October. They also are weak on grasses, which are the predominate summer weeds.

10 Year Summary (May 7 - May 20, 1993-2002):

Full Disclaimers

Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director Cooperative Extension, College of Agriculture and Life Sciences, The University of Arizona.

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