• 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.
    • 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.
    • 1994 Low Desert Upland Cotton Advanced Strains Testing Program

      Husman, S. H.; Jech, L. E.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Forty eight , non -commercially available advanced strains cotton varieties were tested in 1994 on a commercial farm in Gila Bend, AZ. D &PL 5415 and Sure Grow 501 were included as commercial checks for comparison purposes. Ten participating cotton seed breeding companies entered five lines each of materials which were felt to show promise for potential commercialization. Lines were specifically chosen for their potential for yield performance under low desert environmental conditions. Each plot was six rows wide by 38 feet long replicated four times. The test was planted on April 1, 1994 and harvested on November 17 and November 29, 1994 for both the first and second pick respectively.
    • Community-wide Implementation of Samplin and Action Thresholds for Whiteflies in Cotton

      Diehl, J. W.; Ellsworth, P. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Sampling and decision-making plans for managing sweetpotato whiteflies were implemented within 8,000 acres of cotton within the Laveen-Tolleson area of central Arizona. On the average, thresholds utilized for the first whitefly treatment were lower than those recommended, but subsequent treatments were made at about recommended thresholds.
    • 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.
    • Host Preference of Silverleaf Whitefly and Factors Associated with Feeding Site Preference

      Chu, C. C.; Hennberry, T. J.; Cohen, A. C.; Silvertooth, Jeff; USDA-ARS, Western Cotton Research Laboratory, Phoenix, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Silverleaf whitefly (SLW), Bemisia argentifolii, Bellows and Perring, preferred cantaloupe to cotton, broccoli and lettuce in field and greenhouse studies. In the absence of cantaloupe, SLW preferred cotton to broccoli and lettuce. In the field, more eggs and fewer nymphs were found on broccoli than on cotton. Differences in the relative abundance of vascular bundles per unit of leaf area between the four plant species may partly account for differences in oviposition site selection. Vascular bundle volume/unit of leaf tissue volume was 50% greater in cantaloupe than in cotton and broccoli, which in turn were significantly greater than in lettuce. Most SLW on cotton leaves are found on underside leaf surfaces. Distances from top and underside leaf surfaces to the nearest vascular bundles in cotton leaves were 131 and 60 tun, respectively, in the present studies.
    • Cotton Defoliation Evaluations, 1993

      Silvertooth, J. C.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      Two field experiments were carried out in representative cotton producing areas of Arizona to evaluate the effectiveness of a number of defoliation treatments on Pima cotton. These experiments were conducted at Coolidge and Marana. The treatments employed principally consisted of relatively new materials available in Arizona, and were compared to current standard treatments. All treatments showed promise in terms of effectiveness and the results provide a basis for use recommendations in 1995.
    • 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.
    • Precision Guidance Techniques to Reduce Weed Competition and Production Costs in Cotton

      Thacker, Gary W.; Coates, Wayne E.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      The objective of this project is to evaluate the benefits of precision guidance systems as a means of using tillage to kill weeds, and to confine herbicide applications to narrow bands. In cotton, a precision guided close cultivation with a directed spray of MSMA significantly reduced a purple nutsedge stand early on. However this reduction was not significant by the end of the season. For controlling woolly morningglory, the use of a precision guided cultivator equipped with in -row weeding devices resulted in much lower numbers of morningglory weeds, although the differences were not significant at the 95% confidence level. The guidance system kept the implement precisely aligned to the drill rows at a higher speed than was possible with the cooperator's non - precision cultivator. This higher productivity more than offsets the cost of the guidance system and the in-row weeding devices.
    • Short Staple Regional Cotton Variety 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)
      Fifty five short staple varieties were grown in a replicated field trial on the Safford Agricultural Center. Germain's GC 9033, a variety with the same apparent maturity as DP 90 was the top variety for seedcotton yield but came in third place in lint yield behind two varieties from Australia. Average yields were about 200 lbs per acre lower than 1993, which were about 200 pounds per acre lower than in 1992. HW data for the varieties in the trial are included in this report.
    • 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.
    • Determining Soil Moisture for Irrigation Management

      Martin, E. C.; Husman, S.; Wegener, R.; Brown, P.; Johnson, K.; Schnakenberg, L.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      One key component in good irrigation management is the measurement of soil moisture to help determine when to irrigate. In this study, resistance blocks and tensiometers were compared to neutron probe readings to assess how well these devices followed soil moisture and whether the resistance blocks and /or tensiometers could be used to schedule irrigation in cotton production. The resistance blocks were placed at 6, 18, and 30 inches. Tensiometers were placed at 18 and 30 inches. The readings from the resistance blocks and tensiometers were compared to neutron probe readings taken at 6, 18, and 30 inches. The resistance blocks compared well with the neutron probe readings at the 6 inch and 30 inch depth. At the 18 inch depth, there was much scatter in the data. The tensiometers also showed good comparisons at 30 inches and poor comparisons at 18 inches.
    • Nitrogen Management BMPs Parker Valley Demonstration

      Watson, J.; Winans, S.; Sheedy, M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      A nitrogen management demonstration was conducted in the Parker Valley in 1994. Grower nitrogen application practices were compared with nitrogen application recommendations based upon pre plant soil samples plus petiole nitrates and plant mapping data. The only significant difference in amounts applied occurred in May, with grower applied rates exceeding recommended rates. Grower rationale for the application was logical, however, it being dependent upon the uncertainty of irrigation timing in June.
    • 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.
    • 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 Regional Variety 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)
      Ten long staple varieties (including two Pima experimental lines) were tested in a replicated small plot trial on the Safford Agricultural Center in Graham county at an elevation of 2950 feet. Even though the total number of heat units received during the season was nearly as high as the previous year, the average yield was nearly 300 pounds per acre lower. Olvey and Associates OA 304 was the highest yielding variety with a yield of 776 pounds per acre of lint and only two varieties broke the bale and a half mark. Yield and other agronomic data as well as fiber quality data are contained in this paper.
    • 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.
    • 1994 Weather Conditions

      Brown, P.; Russell, B.; Silvertooth, J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      The 1994 cotton production season began with near optimal weather conditions. Temperatures and precipitation during planting and early vegetative growth were near optimal levels and were generally near normal. Summer brought an extended period of high day and night temperatures which began in June and continued through September at most locations. The period of high temperature associated with the monsoon (July and August) coincided with a rapid decline in fruit retention across much of the state. While the monsoon provided the usual rise in night temperature and humidity, summer rainfall was relatively light at most locations. Early fall weather was warm and dry, providing generally good conditions for finishing the crop. Weather conditions then cooled dramatically in the late fall prior to the onset of heavy rains in December. The wet December conditions limited post harvest field work in many locations.
    • 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.
    • 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.