Production Update:

Planting Date: October is the optimum planting date for low desert areas in Arizona, although it is possible to plant alfalfa from September through March. Crop establishment is best in October plantings. Planting too early can result in poor crop establishment due to hot weather, losses from competition from summer weeds, or damage from feeding from whitefly. Winter plantings are at risk for freeze damage, and seedlings with one trifoliate leaf stand a better chance of surviving freeze damage than younger seedlings. Hay production during the first spring is missed in spring plantings and production is delayed until the first summer. Spring plantings tend to be subject to more weed competition and result in a less developed root system compared to fall planting during the establishment year. Delaying planting past October can decrease yields for the life of the stand.

Insect Management: During September many growers will be establishing new stands of alfalfa. Several insect pests can be of concern during stand establishment. When seedling alfalfa plants have emerged monitor the stand for clipped plants. Cutworms, crickets and earwigs will occasionally be abundant enough to severely thin stands by clipping alfalfa seedlings. Sowbugs and pillbugs are crustaceans that damage seedling fields that have not been well tilled and have been known to cause damage in re-seeded fields. The palestriped flea beetle is also occasionally abundant enough to cause severe damage to seedling alfalfa. Treat with an insecticide bait or foliar insecticide when these insects are abundant enough to cause areas of stand loss.

Weed Control: Spraying summer annual weeds this late in the season is sometimes a difficult decision. There are probably 3 months left that these weeds will continue to grow and produce seed. As the days become shorter, summer weeds become more reproductive and spraying now will reduce the weed seed bank for the years ahead. It is not too late to treat summer weeds.

10 Year Summary (August 24, to Sept. 2, 1995-2004):

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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