Yuma County, Arizona
May 17, 2004
(PDF version, 32KB)
Insect Management: Threecornered alfalfa hopper, Spissistilus festinus (Say) ( picture) is a treehopper commonly found in desert alfalfa. Populations buildup in the spring and persist into the fall. They feed by inserting their needle-like mouth parts into stems, sucking out juices. Adult female hoppers girdle stems by depositing eggs, causing the stem and leaves to turn red, purple or yellow above the girdle. Adults are light-green, thick-bodied, triangular insects about 1/4 inch long that readily fly when disturbed. Nymphs are grayish-white, soft bodied, with saw-toothed spines on their backs. Nymphs are confined to the lower portions of the plant and may not be picked up in a sweep net. There are rarely enough threecornered alfalfa hoppers in alfalfa fields to cause economic damage. Definitive monitoring and treatment guidelines have not been developed because threecornered alfalfa hoppers are a sporadic problem in alfalfa.
Weed Control: Mild winters cause some weeds that are
normally summer annuals, to grow like biennials or perennial plants. This
is more common with grasses that with broadleaf weeds. Sprangletop and
sandbur are notorious for overwintering. Overwintered weeds are not controlled
with preemergent herbicides.
10 Year Summary (May 4 to May 17, 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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