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

Production Update:

Summer Cutting Schedule: Alfalfa is often cut before bloom to obtain the highest quality hay possible. Unfortunately, short cutting cycles can deplete alfalfa stands. This is especially true during the summer when nights are hot. Respiration at night consumes carbohydrates deposited in the root during the day and slows the buildup of carbohydrates needed to sustain the first two weeks of the next regrowth cycle. Therefore, delaying cutting until full bloom for at least one cutting during the summer can be beneficial for stand life.

Insect Management: Spider mites in alfalfa may be associated with water stress and infestations may clear up a few days after an irrigation. Infestations start in the lower plant canopy moving upward and leaves are covered with webbing. Spider mites insert needle-like mouth parts into leaves removing plant sap, causing a yellow stippling on leaves. With severe feeding leaves turn brown, become dry and drop from the plant. Feeding damage reduces yield, quality and retards regrowth. Spider mite species in Western Arizona & Southern California include: carmine spider mite (T. cinnabarinus Boisdival) ( picture); desert spider mite (T. desortorum Banks); strawberry mite (T. turkestani Ugarov & Nikolski) ( picture); and twospotted spider mite (Tetrancylus urticae Koch) ( adult picture, feeding damage). Pyrethroid insecticides can flare spider mite infestations. Sulfur may be used to suppress the populations.

Weed Control: Anyone who has worked with the dinitroaniline herbicides such as pendimethelin (prowl), trifluralin (treflan) or benefin (balan) knows that these yellow herbicides are easy to get on yourself and equipment and hard to clean off. WD-40 works well to clean it off. If you spray it on, the yellow wipes right off. WD-40 contains petroleum distillates and is harmful if ingested, inhaled or if it comes in contact with your eyes or skin. Read and follow the directions on the label.

10 Year Summary (July 2 to July 15, 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.

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