Yuma County, Arizona
March 22, 2004
(PDF file 22KB)
Relative Feed Value (RFV): Relative feed value (RFV) is a calculated index of forage quality that is very useful in comparing different types of forages. RFV provides an indication of digestibility of a forage as does total digestible nutrients (TDN), but also includes intake potential. RFV is calculated from both ADF and NDF, whereas TDN is calculated from ADF only.
Insect Management: Several species of Empoasca leafhoppers (picture) occur in alfalfa. Adult leafhoppers are about 1/8” long, bright green, wedge shaped bodies. Nymphs have green wedge-shaped bodies and run rapidly forward, backward or from side to side when disturbed. In the low desert, damage may occur from May through September. Symptoms include a yellow, wedge-shaped area ( picture) at the tip of the leaf and stunting. With the first sign of injury, sample the field with a standard sweep net taking 10 sweeps in 4 to 6 areas over the entire field and count the adults and nymphs. When an alfalfa field is 2 or more weeks from harvest, treat if counts reach 5 leafhoppers per sweep. If alfalfa is within 10 days to 2 weeks of harvest, treat at 10 per sweep. If alfalfa is to be harvested in a few days, early cutting will control leafhoppers. Leafhopper infestations may be confined to the first 50 to 100 feet of the field margin. If this is the case, treat only the field edges where high leafhopper counts of treatable magnitude are found.
Weed Control: Established Bermudagrass (picture)
can be controlled with multiple applications of the highest rates of Select/Prisim
or Poast. One application will often result in suppression for 3-5 weeks
after which the grass will produce regrowth and need to be treated again.
10 Year Summary (March 9, to March 22, 1995-2004):
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, firstname.lastname@example.org Extension Agent, Yuma County
Michael Ottman, email@example.com Agronomy Specialist
College of Agriculture, The University of Arizona.
Eric Natwick, firstname.lastname@example.org UCCE Imperial County - Farm Advisor
University of California, Davis, CA.
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