University of Arizona a dot Cooperative Extension

Alfalfa Report
Yuma County, Arizona
June 17, 2002

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

Production Update:

Hay storage losses: Hay kept in storage loses weight due to a variety of factors. Hay exposed to the weather is most subject to losses, and storage in a barn or covering hay with a tarp can minimize these losses. Hay normally loses weight due to shrinkage or loss of moisture. Hay harvested at 20% moisture may reach a moisture content of less than 10% after 1 to 2 months. Hay also loses dry matter due to respiration even at low moisture contents. Respiration is a normal plant process where sugars are used for maintenance of plant structure and metabolism. Storage losses can range from less than 5% to more than 50% and can be accompanied by a decrease in forage quality.

Insect Management: Alfalfa caterpillar, Colias eurytheme,( Detour signpicture, larvae) is a warm weather pest of alfalfa. There are seven generations per year in the low desert between May ad October. Check fields for alfalfa caterpillars when yellow alfalfa butterflies appear in May. Butterflies are seen flying over tall alfalfa most likely emerged from that field. Eggs are laid singly, standing on end, on the upper surface of leaves in fields with re-growth under 6 inches. Larvae hatch in 3 to 10 days, grow to about an inch long and pupate in approximately two weeks. Alfalfa caterpillars are green with white stripes down their sides and are distinguished from beet armyworm ( Detour signpicture, larvae) by their velvety appearance. Monitor fields weekly from June through October, checking 2 to 3 times per week during periods of heavy infestations. Take 5 sweep counts in 4 to 5 field locations. Check worms for parasitism by pulling heads of an alfalfa caterpillar larva, squeeze out the body contents, and looking for an Apanteles wasp larva. Treat when field counts average 10 non-parasitized caterpillars per sweep.

Weed Control: Annual weeds that are present in fields that are fallow now but will be planted to alfalfa in the fall, can be controlled with repeated irrigations and tillage prior to planting. This is not true with perennial weeds such as bermudagrass and nutsedge. Tillage spreads perennial weeds, it does not control them! Bermudagrass and nutsedge can survive and emerge from several feet below the surface.

Market Summary
Off grade
Past 2 Weeks (June 4 - June 17, 2002)
Last Year (June 4 - June 17, 2001)


10 Year Summary (June 4, 1993 to June 17, 2002):

10 year summary June 4, 1993-June 17, 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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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.

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