University of Arizona a dot Cooperative Extension

Alfalfa Report
Yuma County, Arizona
December 2, 2002

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

Production Update:

Winter Irrigation: Alfalfa water use from November through February averages about 3.5 inches per month in the low elevation desert areas. Winter rainfall cannot usually sustain maximum production in these areas and some supplemental irrigation is required. If we assume an irrigation efficiency of 0.7, then a single 5-inch irrigation every month can meet alfalfa water requirements during the winter on average. The actual irrigation requirement depends on soil type, weather conditions, rainfall, growth of the crop, and other factors. Growers sometimes use the winter as a time to replenish subsoil moisture and apply more water than is actually required by the crop during this time of the year.

Insect Management: Blue alfalfa aphid (Detour signpicture) is a serious pest during the winter and spring months in the low desert. Blue alfalfa aphid is distinguished from pea aphid (Detour signpicture) by uniformly dark antennae. Pea aphids (Detour signpicture) have lighter antennae with dark bands at each joint. The blue alfalfa aphid first appears in December or January when it may be more abundant than pea aphid. Both species are common throughout the spring, but pea aphid is more heat tolerant and may persist into early summer. In susceptible alfalfa varieties, blue alfalfa aphid may stunt growth and infested plants have smaller leaves, shorter internodes, leaf curling, yellowing, and leaf drop. Several species of predacious bugs and parasitic wasps attack these aphids. Sample alfalfa fields weekly when aphids appear, then every 2 to 3 days as numbers approach the treatment threshold of 40 to 50 blue alfalfa aphids per stem.

Weed Control: Some summer annual weeds survive every winter. The most common of these are the grasses, especially sprangletop and sandbur. Preemergent herbicides will not control these survivors when applied in the spring.

Market Summary
Off grade
Past 2 Weeks ( Nov. 19 - Dec. 2, 2002)
Last Year (Nov. 19 - Dec. 2, 2001)


10 Year Summary (Nov. 19 - Dec. 2, 1993-2002):

10 year summary Nov 19 - Dec 2, 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.

The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Any products, services, or organizations that are mentioned, shown, or indirectly implied in this web document do not imply endorsement by The University of Arizona.

Information provided by:
Barry Tickes, Extension Agent, Yuma County
Michael Ottman, Agronomy Specialist
College of Agriculture, The University of Arizona.
Eric Natwick, UCCE Imperial County - Farm Advisor
University of California, Davis, CA.

Yuma County: Field Crops | Farm Notes | Alfalfa Reports | Vegetables

Forages: Crop Mgmt | Soil Mgmt | Irrigation | Alfalfa Reports | Insects | Diseases | Weeds | Pesticides
Home | Other Crops | Forages

For more Arizona Production Ag Information:
Home | Cotton | Veggies| Forages | Grains | Citrus | Crop x Crop | Insects | Diseases| Weeds | Pesticides | News | Weather | Research | Photos | Contacts | General Info. | Site Map

document located at:
Copyright © 2001 University of Arizona,
College of Agriculture and Life Sciences
Webmaster: Al Fournier (