• Comparisons of Lorsban 4E and Spinosad 4SC for Control of Summer Insects in Alfalfa

      Rethwisch, Michael D.; Kruse, Elizabeth; Kruse, Michael D.; Ottman, Michael (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Anew chemistry (Spinosad 4SC) was tested for control of beet armyworm and other summers insects in alfalfa. This product did not control beet armyworms as well as the top of label rate of Lorsban 4E, and at one day post treatment had more beet armyworms than the lowest rate of Lorsban tested At three days post treatment both rates of Spinosad 4SC had fewer beet armyworms than the lowest rate of Lorsban tested. Few differences were noted between Spinosad 4SC for beet armyworm control, although fewer alfalfa caterpillars were noted with usage of the higher Spinosad rate, although significantly more beneficial insects were noted at three days post treatment with the lower rate of Spinosad. Lorsban chemistries significantly lowered yellows and hopperburn damage ratings compared with other treatments and a difference was noted between the two Spinosad rates although Empoasca sp. leafhopper numbers were similar.
    • Influence of Folocron Nitrogen Fertilizer Applied in Summer on Alfalfa Yield During Summer Slump

      Knowles, Tim C.; Ottman, Michael J.; Wakimoto, Victor; Ottman, Michael (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Established alfalfa reportedly does not benefit rom applications of N fertilizer since it is a leguminous crop that is capable of fixing its own N from atmospheric N. Some growers feel that nitrogen (N) fixing nodules found on the roots of the alfalfa plant are ineffective during Arizona's hot summers . Thus, N fertilizer is sometimes applied in early summer to established alfalfa to enhance growth and possibly delay or lessen the severity of summer slump to increase alfalfa tonnage. A field experiment was conducted to determine the effect of inorganic and controlled release N fertilizer applied in summer on alfalfa hay yield at the first cutting during summer slump. Three treatments consisted of an unfertilized check plot, broadcast 18-46-0 applied at 27 lbs. N /acre, and Folocron water run at a rate of 30 lbs. N /acre in August to three year old 'CUF 101' alfalfa grown on a silt loam soil. Maximum alfalfa hay yield at the September cutting (0.91 ton/acre) was obtained without N fertilizer application.
    • Overview of Alfalfa Production and Market Trends in La Paz County

      Knowles, Tim C.; Winans, S. Sherwood; Ottman, Michael (College of Agriculture, University of Arizona (Tucson, AZ), 1997-10)
      Alfalfa producers in the Colorado River region of La Paz County have experienced some shifting trends in markets and production over the last 15 years. Acreage has increased steadily from a low of 25,000 acres in the early 1980's to a high of nearly 45,000 acres in 1997. Average annual alfalfa hay yields in La Paz County have maintained a fairly flat trend ranging from 7.5 to 8.5 tons per acre during this time. Alfalfa hay prices were severely depressed during the summer of 1986, from summer of 1991 through winter of 1992, and during the summer of 1995. In contrast, La Paz County alfalfa hay producers experienced the strongest markets during the winters of 1984, 1990, and 1995. More recently, since the winter of 1996, producers have experienced the strongest alfalfa hay market in the history of La Paz County with on farm prices reaching an all time high of $136 per ton.