• Fertility Management and Calibration Evaluations on Upland and Pima Cotton

      Thelander, A. S.; Silvertooth, Jeffrey C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Various field experiments were conducted during the 1997 and 1998 cotton season involving macro and micronutrient fertilization. A total of six experiments were conducted at various locations in Arizona. Each of the field experiments studied the effects of different nutrients and nutrient combinations on both Upland and Pima varieties. The purpose of these experiments were to evaluate University of Arizona fertility guidelines with respect to soil test results and to possibly fine-tune or calibrate these guidelines for common Arizona soils and cotton growing regimes. Results from these experiments based on soil test information, quantitative plant measurements, and lint yield showed no significant difference due to treatments for all the studies except for a phosphorus study conducted in Graham County.
    • How to Obtain Cotton Advisories from the Internet

      Brown, P.; Russell, B.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Weekly advisories developed by the Arizona Cotton Advisory Program are now available from the Internet. Nineteen location-specific advisories are developed each Monday morning and then transferred to the Main AZMET Internet Web Page located at URL address http://ag.arizona.edu/azmet. To retrieve advisories from the Internet users must 1) log on to the Internet using the procedures required by your Internet service provider; 2) enter the URL for the Main AZMET Web Page; 3) move to the Cotton Advisory sub-page; and 4) select the advisory of interest. Advisories for the most recent week, this year to date, and all of 1998 are available at this Internet address.
    • Integrated Morningglory Control Strategies: Transgenic Cotton and Precision Cultivation

      Knowles, Tim C.; McCloskey, Bill; Wakimoto, Vic; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      A field demonstration was conducted in Mohave Valley to compare cotton morningglory control programs that combined the use of over the top herbicides Roundup Ultra on Roundup Ready cotton (Deltapine 436 RR) or Staple on non-transgenic cotton (SureGrow 125) with and without precision cultivation.
    • Late Season Nitrogen Fertilizer for Cotton

      Knowles, Tim C.; Watson, Jack; Wakimoto, Vic; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Field experiments were conducted during the 1996 and 1997 growing seasons in Mohave Valley to determine the effect of late season nitrogen (N) fertilizer applications on top crop yield potential of upland cotton. A long season production system utilizing late season nitrogen (N) applications through peak bloom (August) was compared to a short season production system in which N was applied through mid-bloom (June). Mid-season N applications were based on UA guidelines utilizing plant mapping and petiole nitrate data for the short season production system.
    • Late Season Pink Bollworm Pressure in the Top Crop of Bt and Non-Bt Cotton

      Knowles, Tim C.; Dennehy, Tim J.; Rovey, Albert; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Green bolls (100/field) were sampled from the uppermost internodes within adjacent fields of Bt (Deltapine 33B) and non-Bt refuge (Hyperformer HS 44 or Deltapine 20) experiencing severe pink bollworm pressure late in the growing season. Evidence of 3rd instar or larger pink bollworm larvae survival was higher in susceptible bolls sampled from transgenic Bt cotton late in the 1998 growing season, compared to that observed late in the 1997 growing season.
    • Marana Pima Test

      Hart, G. L.; Nelson, J. M.; Barney, Glen; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Seventeen pima cotton varieties were grown at the Marana Agricultural Center as part of the national cotton variety testing program. Lint yield, boll size, lint percent and fiber properites are presented in this report.
    • Monitoring Bemisia Susceptibility to Applaud (buprofezin) during the 1998 Cotton Season

      Ellsworth, Peter C.; Sieglaff, D. H.; Yazui, M.; Lublinkhof, J.; Silvertooth, Jeff; The University of Arizona, Department of Entomology & Maricopa Agricultural Center; Nihon Nohyaku, Ltd., Osaka, Japan; AgrEvo USA Co., Wilmington, DE (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Starting in 1993, we developed a field-based protocol for bioassaying sweetpotato whiteflies (SWF) for susceptibility to buprofezin (Applaud®). Since then, we have monitored Arizona SWF populations (up to 5 regions) for susceptibility to Applaud in four out of the last six seasons. We observed no appreciable decrease in susceptibility. Instead, we have observed an increase in susceptibility of present day whiteflies when compared to populations bioassayed in 1993 and 1996, before any Applaud use in the U.S.. This result, however, is likely related to various procedural changes in the bioassay methodology. Nevertheless, our current estimates of whitefly susceptibility are similar to those obtained from various unexposed populations from around the world and to populations we bioassayed in 1997. Differences between our LC50 estimates and those of some other researchers can probably be explained by various procedural differences: 1) method of Applaud application, 2) whitefly stage collected and sources of leaf foliage, and 3) bioassay environmental conditions. Our results also showed each year that Applaud susceptibility does not decline after Applaud application(s) based on commercial paired field comparisons and replicated small and large plot evaluations. In fact, susceptibilities actually marginally increased after an Applaud application. This fact does not alter the recommendation for Arizona to limit Applaud use to one time per crop season, but does provide hope for the development of a sustainable use pattern even if usage continues on non-cotton hosts (i.e., on melons and vegetables under Section 18). Given the tremendous value of this mode of action, however, commodity groups should work together wherever possible to coordinate the usage of this and other valuable compounds so that whitefly generations are not successively exposed to this product.
    • Mortality Factors Affecting Whitefly Populations in Arizona Cotton Management Systems: Life Table Analysis

      Naranjo, Steven E.; Ellsworth, Peter C.; Silvertooth, Jeff; USDA-ARS, Western Cotton Research Laboratory, Phoenix, AZ and 2University of Arizona, Maricopa, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Direct-observation studies were conducted in replicated experimental plots to identify causes and estimate rates of mortality of whiteflies in cotton over the course of six generations from late June through late October. In plots receiving no whitefly or Lygus insecticides, predation and dislodgment were major sources of egg and nymphal mortality, and overall survival from egg to adult ranged from 0-18.2%. Similar patterns were observed in plots treated with the insect growth regulator (IGR) Knack. Applications of the IGR Applaud or a mixture of endosulfan and Ovasyn caused high levels of small nymph mortality and reduced rates of predation on nymphs during the generation immediately following single applications of these materials in early August. Whitefly populations declined to very low levels by mid-August in all plots, and few differences were observed in patterns of whitefly mortality among treated and control plots 4-6 weeks after application. The population crash was associated with an unknown nymphal mortality factor which reduced immature survivorship during this first posttreatment generation to zero. The application of insecticides for control of Lygus in subplots modified patterns of mortality in all whitefly treatments by generally reducing mortality from predation during generations observed from mid-July through August. Parasitism was a very minor source of mortality throughout and was unaffected by whitefly or Lygus insecticides.
    • Narrow Row Cotton Production in Vicksberg

      Knowles, Tim C.; Cramer, Roc; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Deltapine 458B/RR, Deltapine 5415RR, Deltapine 20B, and Deltapine 20 cotton varieties were planted on June 5 into narrow 15 inch wide rows. Populations ranged from 80,000 to 100,000 plants per acre. Seed cotton was stripper harvested on December 17. Although lint yields were somewhat low (1- 2 bale/acre) for this late planted cotton, we learned several important practices for effective narrow row cotton production systems, based on our first years experience in western Arizona.
    • Nitrogen Management Experiments for Upland and Pima Cotton, 1998

      Silvertooth, Jeffrey C.; Norton, Eric R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Two field experiments were conducted in Arizona in 1998 at two locations (Maricopa and Marana). The Maricopa experiment has been conducted for nine consecutive seasons, the Marana site was initiated in 1994. The purposes of the experiments were to validate and refine nitrogen (N) fertilization recommendations for Upland 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. At each location, treatments varied from a conservative to a more aggressive approach of N management. 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 higher, more aggressive, N application regimes did not benefit yields at any location. In 1998, fruit retention levels were low and crop vigor was high. As a result, even slight increases in N fertilization and crop vigor translated into lower yield.
    • Open Cotton Boll Exposure to Whiteflies and Development of Sticky Cotton

      Henneberry, Tom J.; Forlow Jech, L.; Hendrix, D. L.; Brushwood, D.; Steele, T.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Trehalulose and melezitose produced by Bemisia argentifolii Bellows and Perring and thermodetector counts in cotton lint increased with increasing numbers of days of exposure of open cotton bolls in infested cotton plots. Thermodetector counts were significantly correlated to amounts of trehalulose and melezitose. Rainfall of 0.5 inch reduced trehalulose and melezitose in cotton lint within 5 h following the rain. The results suggest dissolution of the sugars followed by runoff as opposed to microbial degradation.
    • Pima Cotton Regional Variety Trial, Safford Agricultural Center, 1998

      Clark, Lee J.; Carpenter, E. W.; Hart, G. L.; Nelson, J. M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Sixteen long staple varieties were tested in a replicated small plot trial on the Safford Agricultural Center in Graham county at an elevation of 2950 feet. The highest yielding variety in this study was OA 340 with a yield of 1021 pounds of lint per acre. It was followed by two other Olvey varieties yielding over 900 pounds per acre, including OA 322 and OA 361 (White Pima). In the adjacent regional short staple cotton trial were three interspecific hybrids from Hazera, an Israeli Seed Company. These hybrids grew like short staple cotton, but the fiber was more like the barbadense parent. These hybrids yielded from 1146 to 1091 pounds per acre. Their data is included at the bottom of the tables for comparison with the other long staple variety values. Yield and other agronomic data as well as fiber quality data are contained in this paper.
    • Pima Regional Variety Test at the Maricopa Agricultural Center, 1998

      Hart, G. L.; Nelson, J. M.; Clark, Lee J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Seventeen Pima varieties were grown in a replicated trial at the Maricopa Agricultural Center as part of the national cotton variety testing program. Lint yield, boll size, lint percent, plant populations, plant heights and fiber properties are presented in this report.
    • Preliminary Evaluation of the "Next Generation" of Bt Cotton

      Sieglaff, D. H.; Ellsworth, Peter C.; Silvertooth, Jeffrey C.; Hamilton, E.; Silvertooth, Jeff; The University of Arizona, Department of Entomology & Maricopa Agricultural Center; Department of Plant Sciences; Monsanto Company, Chesterfield, MO (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      The next generation of Bollgard® cotton was evaluated for agronomic and insecticidal efficacy under central Arizona growing conditions. Two novel lines were compared with their recurrent parents, DP50 and DP50B. There were no seasonlong differences observed among the varieties in most plant development and insect parameters. However, DP50 had significantly lower emergence than the other lines tested (possibly related to seed quality). The lower plant population may have been responsible for greater whitefly abundance observed on two dates mid-season. During early-season ratings of secondary “pests” (15 DAP) (scaled on damage and/or presence), the two test lines received lower ratings for thrips and flea beetle when compared with DP50, DP50B and DP50Bu (untreated for Lepidoptera). However, these difference are likely as a result of the difference in seed treatments that the two test lines received (Gaucho®) and the others did not. This seed treatment does have known activity against thrips and beetle pests. In mid-season, the two test lines received lower ratings for beet armyworm when compared to DP50, DP50B and DP50Bu (although, not significantly different from DP50B or DP50Bu). Efficacy against pink bollworm (PBW) was assessed one time at the end of the season (we were limited to this time, so as to not affect yield), and DP50 was the only variety in which PBW exit holes were observed and PBW larvae collected. However, the low Lepidoptera pressure experienced during the season limited assessments of the two novel lines’ efficacy toward PBW. There was no significant difference in yield (bale/A) among the varieties. Although, one of the test lines had a lower lint turnout than each other variety. The two novel Bollgard lines performed well under our growing conditions, but continued evaluations will be necessary under more conditions and more insect pressures before “varietal” performance and gene efficacy can be assessed adequately.
    • Preplant Micronutrient Fertilizers for Cotton

      Knowles, Tim C.; Artz, Paul; Sherrill, Chip; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Micronutrient fertilizers including zinc, boron, copper, and manganese in their sulfate forms were broadcast applied and incorporated preplant to determine their effects on lint yield of upland cotton.
    • Short Staple Regional Cotton Variety Trial, Safford Agricultural Center, 1998

      Clark, Lee J.; Carpenter, E. W.; Hart, G. L.; Nelson, J. M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Forty eight short staple varieties were grown in a replicated field trial on the Safford Agricultural Center. Excellent yields were recorded, especially considering the late start caused by unseasonably cold weather in April. FM 989, the Australian variety formerly known as IF 1003, produced the highest lint yield of 1601 pounds per acre. Three other varieties, FM 975, AP 4103 and IF 1002, produced over 1500 pound of lint per acre. Agronomic values for the plants at harvest and HVI data for lint quality are tabulated in this paper.
    • Short Staple Variety Trial, Greenlee County, 1998

      Clark, Lee J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Six short staple cotton varieties including two New Mexico acalas varieties and one advanced strain, an Australian varieties and two SureGrow varieties with higher yield potential were tested in this study. New Mexico Acala 1517-95 had the highest lint yield with a yield of 419 pounds of lint per acre. The average yield was about 400 pounds per acre lower than the 6 year average due to a cold spring and a four inch rain that fell in one hour in the middle of July. In addition to lint yields; percent lint, plant heights, plant populations and lint hvi values are shown. A lint yield comparison for 1993 through 1998 is included in this paper.
    • Short Staple Variety Trials in Cochise County, 1998

      Clark, Lee J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Variety trials were grown at two locations and with two different sets of short staple varieties. One trial on the Robbs farm, north of Kansas Settlement, tested two acala varieties and the most promising advanced strain from New Mexico, two short seasoned varieties from SureGrow and one Australia variety. The other trial on the Glenn Schmidt farm, in Kansas Settlement, tested seventeen upland varieties as part of the statewide testing program. The highest yielding variety in the Robbs trial was SG 404 with SG 125 coming in second. In the Schmidt trial, FM 989, an Australian variety that has performed well in Safford, had the highest yield, just over 2 bales per acre.
    • Short Staple Variety Trials, Graham County, 1998

      Clark, Lee J.; Carpenter, E. W.; Walser, R. H.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Two replicated on-farm short staple variety trials were planted in 1998. Fifteen varieties were evaluated on both the Carpenter farm in Thatcher and the Colvin farm near Ft. Thomas. Several new varieties were planted in both studies, including 4 transgenic varieties: DP 90B, BXN 47, DP 90RR and Paymaster 1560BG, 2 varieties from Australia: FiberMax 989 and FiberMax 832, and seven other varieties seen for the first time. Two of the new varieties produced the highest yields; AgriPro 6101 and Phytogen 952 on the Carpenter and Colvin farms, respectively. Other agronomic data from the varieties and HVI values from the lint are also included in this report.
    • Systemic Insecticide Applications at Planting for Early Season Thrips Control

      Knowles, Tim C.; Bushong, Neil; Lloyd, Jim; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1999)
      Temik 15G (6 lbs/acre) or Thimet 20G (8.2 lbs/acre) granular insecticides were applied to 40 inch rows in furrow at planting to cotton growing in Parker Valley, AZ. Moderate thrips pressure (0.5-1.5 thrips/plant) was experienced for the first eight weeks after planting and granular insecticide application. Temik provided better thrips control than Thimet for the first seven weeks after planting this study. Thrips control was similar for the two insecticides beyond eight weeks after planting. Temik application resulted in higher fruit retention levels measured up to 10 weeks after planting, compared to Thimet. However, fruit retention levels measured from 12 to 16 weeks after planting were similar for both Temik and Thimet when cotton plants compensated for early season square losses caused by thrips feeding.