• 1986 Publications of the Western Cotton Research Laboratory, USDA, ARS

      College of Agriculture, University of Arizona (Tucson, AZ), 1987-03
    • Development and Fecundity of Aphis gossypii (Homoptera: Aphididae) on Cotton

      Akey, David H.; Butler, George D.; Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      Cotton aphids. Aphis gossypii. from a source near Phoenix. AZ were found to have an optimal developmental temperature of 27.5 °C with a developmental time of 5 days. Fecundity was optimal at 25 °C with 2.85 mean nymphs/day. Both development and fecundity were linear. The optimal temperature for fecundity was higher than those previously reported for cotton aphids in more moderate climates.
    • Effect of Timing and Herbicide Compatibility in the Application of Burst on Upland Cotton

      Stedman, Sam (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      A field trial was conducted to study the elements of application timing and herbicide compatibility in the use of Burst, a plant growth regulator, and the effects of these two factors on yield of upland cotton. Eight treatments combined the two factors of timing and tank mix. The results showed no significant difference in yield between treatments.
    • Whitefly Adults in Okra-Leaf and Normal-Leaf Cotton

      Wilson, F. D.; Butler, G. D. Jr.; Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      The sweet potato whitefly, Bemisia tabaci (Gennadius) continues to be a serious pest of cotton and an important vector of several virus diseases of fall vegetables. In our search for resistant germplasm, we counted adult whiteflies on cotton cultivars and breeding stocks in AZ and Israel. At Maricopa (MAC), seven of 19 cottons had significantly fewer whiteflies than the check, 'Stoneville 825'. Five of the seven were okra-leaf and two were normal-leaf cottons. In another experiment at MAC, an okra-leaf cotton did not have fewer whiteflies than a normal-leaf one. At several locations in Israel, the okraleaf cotton, BD-12, had significantly fewer whiteflies than a number of normal-leaf cottons.
    • Development of Pink Bollworm Population in Field Cages Containing Deltapine Nextaried and Nectariless Cottons

      Flint, Hollis M.; Wilson, F. Douglas; Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      The development of populations of pink bollworm, Pectinophora gossypiella (Saunders) in 0.003 ha field cages containing 'Deltapine 61' (DPL-61) or a closely related nectariless cultivar 'Deltapine NSL' (DPL-NSL) was studied at the University of Arizona Maricopa Agricultural Center, Maricopa, AZ. Boll infestations were significantly lower in cages of DPL-NSL and total catches of moths in gossyplure-baited Delta traps at the end of the season were lower in these cages. The overall seasonal increases were 15.3- fold for DPL-NSL and 21.4 fold for DPL-61, a highly significant 29% reduction for DPLNSL.
    • Antibiosis in Cotton to Pink Bollworm

      Wilson, F. Douglas; Szaro, Jayne L.; Stapp, Benny R.; Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      Ninety-nine germplasm lines and a resistant check line of cotton, Gossypium hirsutum L., were infested artificially in the field with eggs of pink bollworm (PBW), Pectinophora gossypiella (Saunders), and evaluated for an antibiosis type of resistance to the insect and also for yield potential. All 99 lines came from crosses of well -adapted cultivars, or the nectariless, or nectariless-okra-leaf versions of those cultivars, with previously identified sources of antibiosis (a type of resistance that affects the growth and development of the insect once inside the boll). Twenty-three of the 99 were selected for low PBW damage or for a combination of high lint yield and low damage.
    • Pink Bollworm Resistance and Lint Yield of a Nectariless, Okra-Leaf Germplasm Line

      Wilson, F. Douglas; Flint, Hollis M.; Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      A nectariless, okra -leaf germplasm line of cotton, Gossvpium hirsutum L., designated WC-12NL, was compared with a nectaried, regular leaf commercial cultivar, 'Deltapine 61' (DPL-61) at two locations, Maricopa, AZ and Brawley, CA. At Maricopa, two and three insecticide applications were required for control of pink bollworm, Pectinophora gossypiella (Saunders), on WC-12NL and DPL-61, respectively. At Brawley, six and nine applications were required. Lint yield of WC-12NL was 30% higher than that of DPL-61 at Maricopa, while at Brawley, lint yields were about equal.
    • PREP and DROPP for Controlling Pink Bollworm in 1986 Tests

      Bariola, Louis A.; Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
    • Effects of PREP on Cotton Fruiting, Boll Opening and Boll Weevil Populations

      Henneberry, T. J.; Meng, T.; Deeter, B.; Price, P.; Western Cotton Research Laboratory; Union Carbide (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      Prep applied to cotton on 15, 23, and 29 September reduced numbers of squares, immature green bolls < 1 inch in diameter, and accelerated mature boll opening. Reduced cotton fruiting forms in Prep- treated plots resulted in reduced boll weevil population development.
    • A New Egg Sampling Plan for Pink Bollworm Reduced Insecticide Use by 35 Percent

      Hutchinson, Bill; Beasley, Bud; Henneberry, Tom; Martin, Jeanette; Western Cotton Research Laboratory; Cooperative Extension, University of California (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      During the past two years we developed an egg sampling plan for the pink bollworm (PBW) to provide a more accurate index of moth (target stage) activity than conventional larval sampling. The plan requires that only the presence or absence of eggs laid on bolls be determined to decide when insecticide treatments are needed. Our objective in 1986 was to determine whether egg sampling vs. conventional treatment criteria (e.g., larval infestations, trap catches of male moths, and /or fixed -spray intervals) provided more optimal timing of insecticide applications in a 640-ac field test. Implementation of the egg sampling method in 8 of the 16 fields resulted in an average 35 percent seasonal reduction in insecticide use when compared to conventional methods. Despite the reduction in insecticide use, PBW larval infestations were not significantly different (P = 0.45) in fields samples for eggs vs. fields sampled for larvae from June to September. Yields were also not significantly different (P = 0.40) between the two sets of fields.
    • Treatment of Rootknot Nematodes

      Farr, C. R. (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
    • The Effects of Cotton Leaf Crumple on Greenhouse-Grown Cotton Incoulated at Five Growth Stages

      Mihail, J. D.; Brown, J. K.; Nelson, M. R. (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      The effects of cotton leaf crumple disease on components of yield and on symptom expression were examined for cotton inoculated at five growth stages. As a result of virus infection, the total leaf area was reduced and significant reductions in yield were observed, regardless of plant age at time of inoculation. Yield reductions resulted from a smaller number of bolls set and/or a decrease in boll weight. Foliar symptoms were associated with plants inoculated at all five growth stages, but were observed sooner and were more severe for plants inoculated at the 2-3, 5-8, and 8-10 leaf stages than those inoculated at the 14-16 or 18-20 leaf stages.
    • Varietal Resistance to Alternaria Macrospora

      Cotty, Peter J.; Department of Plant Pathology (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      Greenhouse techniques were developed to evaluate cotton cultivar susceptibility to Alternaria leaf spot. Results indicate that Deltapine Acala 90 is more susceptible to Alternaria leaf spot than other Gossypium hirsutum varieties tested but that it is less susceptible than the G. barbadense varieties Pima S-5 and Pima S-6.
    • Response of Texas Root Rot to Two Sterol-Inhubiting Fungicides and a Soil Sterilant in Graham County, 1986

      Clark, Lee J.; Cluff, Ronald E. (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
    • Application of Systemic Fungicides Through Subsurface Drip Irrigation for Control of Phymatotrichum Root Rot

      Olsen, Mary W.; George, Steven; Heathman, Stanley (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      Application of two systemic fungicides, propiconazole (Tilt) and triadimenol (Summit), through subsurface drip irrigation resulted in a significant reduction in the number of dead plants in a Phymatotrichum-infested cotton field. The percent reductions in Tilt treatments were 72% in 1985 and 66% in 1986 and in Summit treatments were reduced 90% in 1985 and 70% in 1986.
    • A Predictive System for Disease Incidence of Black Root Rot of Cotton

      Mauk, P. A.; Hine, R. B. (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      A quantitative technique has been developed to assay cotton soils for populations of Thielaviopsis basicola, a soil occurring fungus that causes the seedling disease of cotton known as Black Root Rot. The procedure utilizes a soil dilution technique with a carrot extract agar containing etridiazol, Mystatin, streptomycin sulfate, chlortetracycline, calcium carbonate and PCNB. Populations of the fungus have been monitored from April to December, 1986 in a heavily infested Pima S-6 field in cooperation with Bob Cockrill, a Coolidge grower. When field soils containing approximately 600 propagules of the fungus per gram of air dry soil were planted to Pima S-6 in the laboratory, 75-100% and 50-75% cortical decay occurred at 20 and 28 C, respectively. This seedling damage was related to subsequent reduced seedling vigor.
    • The Evolution of Subsurface Drip Irrigation on Sundance Farms

      Wuertz, Howard; Tollefson, Scott (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
    • Irrigation Termination Under a Volunteer Grower Boll Weevil Program

      Farr, C. R. (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
    • Comparison of Increased Irrigation Frequency

      Farr, C. R. (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
    • Scheduling Irrigations on Cotton Based on the Crop Water Stress Index

      Garrot, Donald J. Jr.; Fangmeier, Delmar D.; Husman, Stephen H. (College of Agriculture, University of Arizona (Tucson, AZ), 1987-03)
      The Crop Water Stress Index (CWSI) was used to schedule irrigations on drip irrigated cotton research plots in Tucson and on eight acre furrow irrigated fields at the Marana and Maricopa Agricultural Centers. Scheduling irrigations when plots reached 0.30 CWSI units resulted in highest yields with 1403 lbs/acre cotton lint using 33.8 inches of water. The Marana and Maricopa fields yielded 1322 lb/acre on 28 inches and 1767 lb/acre on 58 inches of water, respectively.