Production Update:

Irrigation timing: Alfalfa is most susceptible to water stress immediately after cutting. Irrigating as soon as possible after cutting or applying the previous irrigation later in the cutting cycle can promote early growth. However, irrigating too soon after cutting before some regrowth has occurred can lead to scald damage if temperatures are over 100 degrees and the soil is saturated for more than 30 hours. Also, irrigating too late in the irrigation cycle can result in soil compaction and permanently damage the alfalfa stand. Nevertheless, with these constraints in mind, encouraging early growth by irrigation management will result in greater productivity

Insect Management: Webworms (picture), such as alfalfa webworm, beet webworm and garden webworm, are occasionally found in desert alfalfa. The larvae of these small moths are slender, usually greenish yellow, stripped or spotted caterpillars which may reach an inch in length. The larvae devour leaves beneath silken webs on alfalfa leaves. They may be found on the upper parts of plants in summer and fall. They are not known to cause serious economic damage. Harvesting the infested hay usually greatly reduces the numbers in the next crop cycle.

Weed Control: Balan and Eptam are the only preplant herbicides registered on alfalfa. Trifluralin has reduced new stands by 40 to 60 percent in our tests. Prowl in not registered on alfalfa and has also hurt new stands in our tests except where it was mechanically incorporated prior to planting

10 Year Summary (July 27, to August 9, 1995-2004):

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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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