• A Community-wide Approach to Whitefly Management

      Diehl, J. W.; Ellsworth, P. C.; Husman, S. H.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      An extension supported, grower controlled, community pest management group was initiated in the Laveen and Tolleson communities of Arizona with the management of sweetpotato whitefly (SPWF) as its initial focus. The three functions of this group were awareness, communication, and cooperation. Increased awareness and communication of pest management problems and solutions were achieved through regular meetings and newsletters. Community cooperation took the form of a community-based overwintering survey and a sticky trap network. These two cooperative activities served both an educational and a research function. From the overwintering survey and the sticky trap network, growers learned about the overwintering habits and movement dynamics of whiteflies in their area, the limits of sticky traps for SPWF detection, the need for the reduction of SPWF populations before they move onto cotton. and the need for careful infield sampling of SPWF populations.
    • The Effects of PIX Application Timing on Upland Cotton Lint Yield and Growth and Development Parameters

      Husman, S. H.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Six commercial scale field studies were conducted from 1991-1993 to further evaluate and predict Upland cotton yield and development responses to PIX application timing as a function of cotton growth and condition. Treatments imposed intended to further clarify some response trends observed in previous years of field studies. Treatments were all at the maximum label rate of one and one half pints with application timing the main variable. Timing was based on heat unit accumulation and resultant growth stage since date of planting. Two of the six studies resulted in significant lint yield increase of roughly one hundred pounds across all PIX treatments in contrast to the untreated check. The two studies which resulted in lint yield increases both had height: node ratio measurements in excess (vegetative) of previously defined guidelines.
    • Initial Post Plant Irrigation Effects on Low Desert Upland Cotton Yields Using Leaf Water Potential Measurements

      Husman, S. H.; Barrot, D. J. Jr.; O'Leary, J. W.; Moore, M.; Wegener, R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Leaf water potential (LWP) measurements using a pressure chamber were used to determine optimum timing of the first irrigation following planting on Upland cotton in 1992 and 1993. Previous studies have indicated that leaf water potentials are dependent on the vapor pressure deficit (VPD) of the surrounding air. As a result, the VPD was accounted for in the development of a Leaf Water Potential Index (LWPI). The field studies consisted of three irrigation treatments with four replicates arranged in a randomized complete block design (RCB). Targeted treatment thresholds were 0.15 LWPI (wet), 0.30 LWPI (medium), and 0.45 LWPI (dry). Timing of the first irrigation for the 1992 study occurred at 36, 53, and 63 days after planting. Timing of the 1993 first irrigation occurred at 50, 61, and 77 days after planting for the wet, medium, and dry treatments respectively. There were no significant lint yield differences between irrigation treatments in both 1992 and 1993.
    • Methanol Effect on Upland Cotton

      Husman, S. H.; McCloskey, W. B.; Molin, W. T.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      The effects of foliar applied methanol on Upland cotton were measured in a large field study in Phoenix, AZ. An untreated check was compared to weekly applications of 30% methanol, 30% methanol plus 1% Urea and 0.1 % Fe EDTA, and 1% Urea and 0.1% Fe EDTA. Plant growth and development, photosynthesis, transpiration, soil water use and lint yields were measured. There were no differences in any of the measured variables between treatments.
    • Upland Cotton Variety Resposne to Row Spacing

      Husman, S. H.; Silvertooth, J. C.; Jech, L. E.; Wegener, R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      An Upland cotton row spacing study evaluation 30 in. vs. 38 in. rows was conducted in the Gila Valley of western Maricopa County in 1993. In addition, six Upland varieties were also evaluated on both the 30 and 38 in. row configurations. There were no row spacing differences in yield among five of the six varieties. Sure Grow 1001 had significantly lower lint yields when produced on 30 In. rows. DPL 5415 had significantly higher lint yields that the other five tested varieties on 38 in. rows. There were no variety differences in the 30 in. rows.