• Plant Population Evaluation for Upland Cotton

      Norton, E. R.; Silvertooth, J. C.; Stedman, S. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Plant population management is an important aspect of cotton production. Recommendations for optimum plant densities range from 25,000 - 45,000 plants per acre (ppa). A study was conducted in Pinal county in 1994 to evaluate the recommendations already given. Plant densities for this study ranged from approximately 18,000 - 65,000. Yields increased with populations of 18,000, 28,000, and 39,000 ppa. For populations of 43,000 and 65,000 ppa a corresponding decrease in yield from 39,000 ppa was observed. This study serves to reconfirm the recommendations for optimum plant densities.
    • Effect of Plant Water Status on Defoliation of Pima Cotton

      Nelson, J. M.; Hart, G. L.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      A study was conducted at the University of Arizona Maricopa Agricultural Center, Maricopa, AZ in 1994 to determine the influence of plant water status at the time of defoliation on effectiveness of defoliants and yield of Pima cotton. Several irrigation termination dates were used to achieve different levels of plant water stress at the time defoliants were applied. A single application of defoliants did not provide adequate defoliation under the conditions of this test. The earliest irrigation termination date resulted in the highest defoliation percentage. High CWSI values at the time defoliants were applied were related to the highest defoliation percentages, but were not necessarily related to satisfactory defoliation. The CWSI appears to have limited value as a guide to determine when to defoliate Pima cotton.
    • Evaluation of Late Season Pix™ Applications

      Norton, E. R.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      The effects of late -season Palm on the growth characteristics and yield of Upland cotton was examined in this study. Three treatments were imposed late-season (3447 HUAP), 1, a check plot, receiving no Pix™, 2 receiving 0.75 pt/acre, and 3; receiving 1 pt/acre. The imposed treatments did not have a statistically significant effect on plant growth characteristics or earliness nor were there any significant overall yield differences detected among treatments.
    • Upland Regional Cotton Variety Test at the Maricopa Agricultural Center, 1994

      Hart, G.; Nelson, J. M.; Clark, L. J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Twenty-seven upland cotton varieties were grown in a replicated test at the Maricopa Agricultural Center as part of the National Cotton Variety Testing Program. Lint yield, boll size, lint percent, plant population and fiber property data are presented in this report.
    • 1993 Parker Valley & Mohave Valley Short Staple Cotton Variety Trial

      Hood, L. R.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Two short staple cotton variety trials were conducted in the Colorado River Basin. One trial was located in the Parker Valley and one in the Mohave Valley. Ten varieties from various seed companies were entered in each test. Yields varied considerably among varieties and locations. However, these trials among others provides evidence that current variety choices are viable components of Arizona cotton production.
    • Short Staple Variety Trial, Greenlee County, 1994

      Clark, Lee J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Nine short staple cotton varieties including five New Mexico acalas, four California acalas were tested in the 1994 variety study. The highest yielding variety was 1517-91 with a lint yield of 1009 pounds per acre. The average yield was nearly 200 pounds per acre higher than the previous three years. In addition to lint yields; percent lint, plant heights, height to node ratios and plant populations are shown. A lint yield comparison for 1991, 1993 and 1994 is included in this paper.
    • Short Staple Cotton Advanced Strains Trial, Safford Agricultural Center, 1994

      Clark, L. J.; Carpenter, E. W.; Hart, G. L.; Nelson, J. M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Twenty six short staple advanced strains/varieties were grown in a replicated field trial on the Safford Agricultural Center. SureGrow SGX247 was the highest yielding cultivar in the trial with a lint yield of 1628 pounds per acre. The exciting feature of this trial is that the top two swains exceeded the highest yield in the Regional variety trial by 100 to 150 pounds of lint. This is the first time that so many advanced strains were tested in a given year. The site at Safford gives cotton breeders an insight as to how their advanced strains or new varieties will perform in the high deserts of Arizona and New Mexico. HVI data for the varieties in the trial indicate that the average fiber length was greater than 1.11 inches and the average fiber strength was greater than 30 grams/tex.
    • Pima Cotton Improvement

      Moser, H. S.; Percy, R. G.; Ray, I. M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      The objective of this study was to evaluate the performance of five experimental lines (P73, P75, P76, P80, and P81) with two commercial varieties ('Pima S-6' and 'Pima S-79 of Pima cotton. All seven strains were grown in replicated strip tests at four locations across the Pima belt in 1994. While none of the experimental lines produced significantly more lint than the best Pima variety at any site, some of them possess traits that are valuable to Pima cotton breeders. P73 has long and strong fiber. P76 is a high yielding, early maturing line that produces long and strong fiber. P80's lint yields are similar to Pima S-7, but it is significantly earlier.
    • Comparison of Irrigation Scheduling Methods in Cotton Production

      Martin, E. C.; Pegelow, E. J.; Stedman, S.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Three different irrigation scheduling techniques were compared in this study; aerial infrared, hand -held infrared, and neutron moisture gage measurements. There were four treatments with three replications of each. Treatment one was scheduled using aerial infrared imaging and analyzes performed by Agrometrics, Inc. Treatment two was scheduled using a hand -held infrared gun. Irrigations for this treatment were initiated at a crop water stress index value of 0.3. Treatments three and four were scheduled using neutron probe measurements. Treatment three was irrigated at 45% depletion of the available soil water. Treatment four was irrigated at 45% depletion of the available soil water until mid-bloom, when the strategy was changed to irrigate at 35% depletion. Yield results showed no significant difference between the treatments.
    • Pima Regional Variety Test; Maricopa Agricultural Center, 1994

      Hart, G. L.; Nelson, J. M.; Clark, L. J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Nine Pima varieties and experimental strains were grown in a replicated trial at the Maricopa Agricultural Center. Lint yield, boll size, lint percent, plant population and fiber property data are presented in this report.
    • Irrigation Frequency and Cotton Yield in Short-Season Cotton Systems

      Chu, Chang-chi; Henneberry, Thomas J.; Silvertooth, Jeff; USDA-ARS, Western Cotton Research Laboratory, Phoenix, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      We tested the hypothesis that small frequent irrigations during the July cotton peak fruiting stage would result in better fruiting and higher cotton yields than the same amount of water applied less frequently. Over three years under a short - season production system, irrigation intervals of every 5-d with 42 mm of water applied at each irrigation increased cotton lint yield by 5-11 % compared to irrigation intervals of 10- and 15-d with 80 and 130 mm of water applied at each irrigation, respectively. The results show that small, frequent furrow irrigations during cotton fruiting are highly effective in reducing water deficit during critical growth stages and improved lint production in a short - season cultural system. Soil salt content in the top 15 cm of soil was not increased after three years of study.
    • Effect of Soil and Foliar Applied Potassium on Pima and Upland Cotton at Two Arizona Locations

      Galadima, A.; Silvertooth, J. C.; Unruh, B. L.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Due to increasing emphasis and interest being placed on cotton (Gossypium spp.) fiber quality as well as yield benefits associated with potassium (K) fertilization, two studies were conducted in 1994. These studies with those before them were aimed at assessing the agronomic necessity of K fertilization in Arizona cotton production. The locations of the trials included Maricopa Agricultural Center (Casa Grande sandy loam) and Safford Agricultural Center (Pima clay loam). At the Safford location, both Upland (G. hirsutum L., var. DPL 90) and Pima (G. barbadense L., var. S-7) cotton were planted with treatments that included both soil and foliar K applications. The trials at Maricopa Agricultural Center included four foliar K applications over the growing season on Pima (G barbadense L., var. S-7) cotton. The results of the experiments at both locations indicated no lint yield responses to K fertilization by either Upland or Pima cotton.
    • 1994 Cottonseed Treatment Evaluations

      Norton, E. R.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Cottonseed was treated with several fungicide treatments in an effort to protect the seed and seedling from disease. Seed germination and vigor was evaluated in three Arizona locations; Maricopa, Marana, and Safford. Stand counts were taken on two separate dates after emergence at both Safford and Marana and once at Maricopa and percent emergence was calculated. Among the three locations two, Marana and Safford, showed significant differences among treatments. Treatment number 5 placed first at both locations where significant differences were found. The untreated control placed last in the ranking at both Marana and Safford for all dates of sampling.
    • Cotton Leaf Curl Virus, A Threat to Arizona Cotton?

      Nadeem, Athar; Xiong, Zhongguo; Nelson, Merritt; Silvertooth, Jeff; Department of Plant Pathology, University of Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      A serious virus disease of cotton in Pakistan is distantly related to cotton leaf crumple in Arizona. It is much more destructive on cotton than leaf crumple, and has never been found in the western hemisphere. Cotton leaf crumple in Arizona causes only modestly damaging midseason infections, while leaf curl, has had a major impact on the crop in Pakistan. Modern transportation and the increasing movement of living plants in global trade has resulted in them recent introduction of a similar disease of another crop to the western hemisphere.
    • Telone II® and Temik® Efficacy on Rootknot Nematodes in Cotton

      Husman, S.; McClure, M.; Lambeth, J.; Dennehy, T.; Deeter, B.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Field studies were conducted at four western Maricopa County commercial sites in 1994 to determine whether Temik 15G® would suppress rootknot nematode at low to moderate populations. Three of the experiments were on Upland D +PL 5415 with the fourth on Pima S-6. Sites were chosen based on pre- season sampling with individual field populations ranging from 0.005 (low) - 3.6 (high) rootknot nematode juveniles per cubic centimeter (cc) of soil volume. Each study consisted of four treatments with six replications. The following treatments were used at all test sites: (1) Untreated check, (2) 5 lbs. Temik 15G at planting, (3) 5 lbs. Temik 15G at planting, 15 lbs. Temik 15G sidedressed at pinhead square, (4) 5 gal. Telone 11® pre-plant. Sampling for thrips and lygus was conducted at all test sites to provide insight regarding yield effects resulting from control of insect versus those due to suppression of nematode. There were no significant yield differences between the untreated check and either Temik treatment. However, significant yield increases were measured with Telone versus all treatments at all locations. Insect pressures were minimal in all cases. Temik 15G did not suppress nematode damage at any population level.
    • Nitrogen Management Experiments for Upland and Pima Cotton, 1994

      Silvertooth, J. C.; Norton, E. R.; Unruh, B. L.; Navarro, J. A.; Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Three field experiments were conducted in Arizona in 1994 at three locations ( Maricopa, Marana, and Safford). The Maricopa and Safford experiments have been conducted for six consecutive seasons, with consistent plot locations; the Marana site was initiated in 1994. The purposes of the experiments were to validate and refine nitrogen (N) fertilization recommendations for both Upland and Pima cotton. The experiments each utilized N management tools such as pre-season soil tests for NO₃⁻-N, in-season plant tissue testing (petioles) for N fertility status, and crop monitoring to ascertain crop fruiting patterns and crop N needs. Results at each location revealed a strong relationship between the crop fruit retention levels and N needs for the crop. This pattern was further reflected in final yield analysis as a response to the N fertilization regimes used. The effects of N fertility levels have been consistently evident in crop maturity and its relationship to lint yields.
    • Bioassay Results in Field Persistence of Two Pink Bollworm Parasitic Nematodes

      Lindegren, J. E.; Henneberry, T. J.; Forlow Jech, L. J.; Burke, R. A.; Silvertooth, Jeff; USDA-ARS, HCRL, Fresno, CA; USDA-ARS, WCRL, Phoenix, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Steinernema carpocapsae (Weiser) and S. riobravis Cabanillas, Poinar and Raulston applied in the field at the rate of 1 billion nematodes /acre equivalent persisted in the soil for 63 and 6 days, respectively. Persistence of S. riobravis in the field may offer the potential for introduction and permanent establishment of this nematode for pink bollworm (PBW), Pectinophora gossvpiella (Saunders), control in southwestern cotton growing areas.
    • The 1995 Arizona Cotton Advisory Program

      Brown, P.; Russell, B.; Silvertooth, J.; Ellsworth, P.; Stedman, S.; Thacker, G.; Husman, S.; Cluff, R.; Howell, D.; Winans, S.; Grumbles, R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Arizona Cooperative Extension generates and distributes weather -based Planting Date and Cotton Development Advisories for 11 cotton production areas (Marana, Laveen, Paloma, Litchfield Pk., Pinal Co., Parker, Mohave Valley, Queen Creek, Safford, Yuma Valley, and Aguila). Planting Date Advisories are distributed from mid- February through the end of April and stress 1) planting cotton varieties according to heat unit accumulations rather than calendar date and 2) the importance of soil temperature to good germination. Cotton Development Advisories are distributed from early May through mid -September and provide updates on crop development, insects, weather and agronomy. The Cotton Advisory Program will continue in 1994 and growers may obtain the advisories by mail or fax from the local county extension office, and by computer from the AZMET computer bulletin board. Improved normal weather statistics and the addition of an advisory for Cochise County are the main changes planned for the 1995 program.
    • Multiple Plant Growth Regulator Use on Short Staple Cotton

      Hood, L. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      A field trial was conducted during the 1992 & 1993 growing seasons to evaluate the activity of Cytokin and Pic applied alone or in combination to short staple cotton. The Cytokin treatment significantly increased tint yield over the other treatments in 1992. There were no statistically significant seed cotton differences between the non - treated check and any treatment in 1993. Fruit retention remained high throughout 1992 and very high throughout the 1993 season. Under high fruiting conditions, use of a plant growth regulator would not normally be recommended.
    • Silverleaf Whitefly: Honeydew Sugars and Relationship to Sticky Cotton

      Henneberry, T. J.; Hendrix, D. L.; Perkins, H. H.; Forlow Jech, L.; Burke, R. A.; Silvertooth, Jeff; USDA-ARS, Western Cotton Research Laboratory, Phoenix, AZ; USDA-ARS, SAA, Clemson, SC (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      In cotton plots heavily infested with silverleaf whitefly (SLW), Bemisia argentifolii Bellows and Perring, amounts (mg /g of lint) of sugar (fructose, glucose and sucrose combination) on lint from tagged bolls, varied but showed a general trend to increasing amounts with increasing time of exposure (days) for 52 days. Minicard lint stickiness ratings responded in a similar manner and all values were above acceptable thresholds. Lint from harvested mature open bolls that were exposed on trays suspended in the interior of SLW infested cotton plots showed increasing amounts of sugar and higher minicard ratings after 6 days. Amounts of sugar and minicard ratings were drastically reduced following rains of 1.5 inches.