• 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.
    • Dry Matter Accumulation by Upland and Pima Cotton

      Unrah, B. L.; Silvertooth, J. C.; Steger, A. J.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Several investigations of dry matter accumulation by Upland cotton (Gossvpium hirsutum L.) have been conduced, however no investigations of this type have included American Pima cotton (G. barbadense L.). We conducted a study to describe the total dry matter accumulation and partitioning of that dry matter into various plant parts for both Upland and Pima cotton. During the growing seasons of 1990, 1991, and 1992 at two south-central Arizona locations, both Upland (var. DPL 90) and Pima (var. S-6) cotton were grown. Beginning 14 to 20 d after emergence, whole cotton plants were removed and cotton plants were separated into stems, leaves (including petioles), burs (carpel walls), lint, and seeds. The bur fraction, also included squares, flowers, immature bolls, and burs from mature bolls, Regression analyses was used to model nutrient uptake as a function of both days after planting (DAP) and heat units after planting (HUAP). Regression analyses indicated that HUAP was equally good, and in most cases superior to using DAP to model dry matter accumulation and partitioning within both Upland and Pima cotton. The general patterns of dry matter partitioning for Upland and Pima cotton are similar. However, Upland and Pima differ in the relative amount of dry matter incorporated into reproductive (bur, seed, and lint) and vegetative (leaf and stem) structures. Upland cotton produced 3527 lb /acre more total dry matter than Pima cotton. At the end of this study the vegetative /reproductive ratio for Upland was 83% compared to 70% for Pima. Upland was also more efficient at partitioning lint dry matter within the total dry matter of the reproductive structures. Dry matter incorporated into reproductive structures was 23% lint for Upland, compared to only 14% lint in Pima cotton. In summary, Upland placed more total dry matter into reproductive structures, and of the amount placed into reproductive structures, a greater proportion was incorporated into lint, when compared to Pima cotton.
    • Evaluation of Trap Crops as a Component of a Community-Wide Pink Bollworm Control Program

      Thacker, Gary W.; Moore, Leon; Ellsworth, Peter C.; Combs, Jack; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Trap crops were evaluated as a part of a community -wide pink bollworm (PBW) control program. We measured extraordinarily high numbers of PBW larvae in the trap crops in 1992, which indicated that the trap crops were attracting PBW moths from wide areas. However, we have no direct way of measuring any effect this would have on the main crop. Overall PBW populations were very low in 1993. While PBW numbers drastically declined in the community, this study offers no conclusive evidence as to whether trap crops are an effective component of a community-wide IPM program.
    • Arizona Upland Cotton Variety Testing Program

      Silvertooth, J.; Norton, R.; Clark, L.; Hood, L.; Husman, S.; Cluff, R.; Stedman, S.; Thacker, G.; Silvertooth, Jeff; University of Arizona Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Ten field experiments were conducted across the cotton growing areas of Arizona in 1993 for the purpose of evaluating Upland cotton varieties in terms of adaptability and performance. Five commercial cottonseed companies participated in the program. Two varieties were submitted from each company at each location. Experiments were conducted on grower -cooperator fields in each case. Locations used in the program spanned the range of conditions common to cotton producing areas of the state from about 500 ft. to 4,000 ft. elevation. Results indicated a broad range of adaptability and competitiveness on the part of each of the participating companies and their representative varieties. Each of the companies offers a compliment of varieties that can serve to match various production strategies commonly employed in the state as well as showing a strong capacity to be regionally adaptive.
    • 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.
    • 1993 Cotton Seed Treatment Evaluations

      Silvertooth, J. C.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      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 and percent emergence was calculated. Among the three locations only one, Marana, showed significant differences among treatments. The highest percent emergence being seeds treated with Nu-Flow ND at a rate of 7.5 fl oz/cwt. The untreated control placed last in the ranking at this location.
    • Control of Sweepotato (Silverleaf) Whitefly, Bemisia Tabaci, on Cotton in Paloma, Arizona

      El-Lissy, O.; Antilla, L.; Staten, R. T.; Leggett, J. E.; Walters, M.; Silvertooth, Jeff; Arizona Cotton Research and Protection Council, Phoenix, AZ; USDA-Animal and Plant Health Inspection Service, Phoenix, AZ; USDA-ARS-Western Cotton Research Laboratory, Phoenix, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      A large scale for the control of sweetpotato (silverleaf) whitefly, Bemisia tabaci, (SPW) was carried out in Paloma and Painted Rock near Gila Bend, Arizona, on approximately 6,156 ha of cotton during the 1993 season. Within the program area 40 fields were randomly selected for comparison with 15 fields in each of 2 locations outside the program. They were identified as check east (approximately 11 k northeast of the program) and check west (approximately 3 k west of the program). Whitefly populations in both check areas were controlled according to individual grower protocol. On a weekly basis, adult counts were taken from all 4 edges and the centers of each field using the oil pan technique. Insecticides were applied aerially in the program area on the full field or edges based on population density recorded from pan samples. Insecticide combinations were rotated weekly in an attempt to reduce the potential for the development of pesticide resistance. During the 16 -week evaluation period SPW adults were significantly higher in check east and check west than the program area by 2- and 6-fold respectively; eggs were higher by 3- and 39 fold, respectively; and nymphs were also significantly higher in check east and check west by 3- and 60-fold respectively. Ginning records for 1993 indicate approximately a 20% increase in yield in the program area a 5% increase in check east and a 40% decrease in check west as compared to 1992. These results demonstrate that an area -wide approach, utilizing edge treatment where possible, based on extensive field sampling regimens represent an important integrated strategy in a successful whitefly control program.
    • Short Staple Variety Trial, Greenlee County, 1993

      Clark, Lee J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Ten short staple cotton varieties including four New Mexico acalas, one New Mexico experimental acala, three California acalas, one hybrid acala and a rust resistant variety from Mexico were tested in the 1993 variety study. The highest yielding variety was Maxxa with a lint yield of 832 pounds per acre. In addition to lint yields; percent lint, boll weights, plant heights and plant populations are shown. Average boll weights are compared between this location and three other elevations varying from 1400 feet to 4100 feet above sea level.
    • Numerical and Binomial Sequential Sampling Plans for Adult Bemisia Tabaci in Cotton

      Naranjo, S. E.; Flint, H. M.; Henneberry, T. J.; Silvertooth, Jeff; USDA-ARS, Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Fixed-precision numerical and binomial sequential sampling plans are reported for adults of Bemisia tabaci (Strain B) on cotton. Both plans are based on whole leaf sample units from the fifth mainstem node (counted from the terminal). Numerical sampling plans allow for the efficient estimation of adult population density. Numerical sampling stop lines are presented relating the cumulative number of adults counted to the number of leaves examined for two levels of statistical precision. Binomial plans were developed to allow classification of adult population density for pest management decision -making application. These plans were devised for three action threshold levels; 5, 10 or 15 adults per leaf Binomial sampling stop lines are presented relating the cumulative number of infested leaves to the number of leaves examined as an aid for determining the need for population suppression.
    • Cultural and Management Practices for Pima Cotton Production

      Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      The good use of cultural or agronomic practices is fundamental to the production of high yields and quality of American Pima cotton. In order for Pima farmers to maintain viable production operations, a continual review and improvement upon the existing set of cultural practices are in order. Basic aspects of crop production such as planting date management, soil fertility and plant nutrition, plant growth regulator use, crop termination, and defoliation are reviewed in this paper in relation to American Pima cotton production. Specific attention is also given to potassium (K) fertility management and Alternaria leaf spot regarding new aspects of potential management needs.
    • Evaluation of Date of Planting on the Yield of Several Upland Varieties at Marana, 1993

      Silvertooth, J. C.; Brown, P. W.; Norton, E. R.; Unrah, B. L.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      A single field experiment was conducted in 1993 at Marana, Arizona (2,000 ft. elevation) to evaluate the response of three Upland cotton varieties to three dates of planting. Planting dates ranged from as early as 6 April to 11 May. Planting date was a significant effect for all varieties and revealed a substantial drop in yield with delays past 20 April in 1993, which corresponded to 568 heat units (HU, 86/55 °F thresholds) accumulated since 1 January.
    • Chemical Control of the Sweetpotato Whitefly in Cotton

      Watson, T. F.; Telles, A.; Peña, M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Various registered and experimental insecticides were evaluated for sweetpotato whitefly (Bemisia tabaci Gennadius) control in several field experiments at Yuma, Arizona in 1993. Best controls were obtained with insecticide mixtures, particularly a pyrethroid and an organophosphate, rather than with individual materials. Results of these experiments indicate that severe population densities can be controlled using insecticide combinations, even though sustained use of these insecticides would probably lead quickly to the development of resistance.
    • Short Staple Variety Trials in Cochise County, 1993

      Clark, Lee J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Variety trials were grown at two locations and with two different sets of short staple varieties. One trial, north of Kansas Settlement, tested nine acalas and one rust resistant variety from Mexico. The other trial, south of Kansas Settlement and east of Pearce, tested three acalas and nine upland varieties. Top yielding varieties were Maxxa, in the acala trial and DPL 2056 in the upland trial. Yields were lower than expected due to adverse weather conditions, including hail.
    • Cotton Producers Working in Unison: The Multi-Component IPM Program in Marana, AZ

      Thacker, Gary W.; Ellsworth, Peter C.; Moore, Leon; Combs, Jack; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Cotton growers in Pima County, Arizona are working together to implement a community-wide Integrated Pest Management program. Participation is voluntary; and is unanimous in at least some components of the program. The IPM program employs many control components aimed at the pink bollworm, the principle cotton insect pest in the area. Growers time the deployment of the control components to act in unison throughout the community. Insecticide applications in the area have trended downward since the program began in 1991, indicating that we are making progress toward our goal of reducing the reliance on pesticides.
    • Sweetpotato Whitefly (Bemisia Tabaci Gennadius) Population Relationships to Cotton Yield and Quality

      Chu, C. C.; Henneberry, T. J.; Akey, D. H.; Prabhaker, N.; Perkins, H. H.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Sweetpotato whitefly (SPWF) Bemisia tabaci Gennadius strain B has been a devastating pest of cotton in Arizona and California in recent years. Management systems involving cultural procedures, SPWF population monitoring crop sanitation, crop sequencing chemical control and other technology are developing slowly. SPWF population information in relation to cotton yield and quality losses are urgently needed Preliminary studies with cotton insecticide treatments initiated each week from shortly after cotton seedling emergence to late in the cotton season were conducted at the Irrigated Desert Research Station, Brawley, CA in 1993. The results suggest significant correlations for numbers of SPWF per leaf disc from cotton leaves vs. cotton yield and lint stickiness. Cotton lint yield was negatively correlated to all stages of SPWF populations (-0.783 or higher). Lint stickiness was high positively correlated to SPWF populations (0.707 or higher) and cotton defoliation was positively correlated to SPWF populations (0.876 or higher).
    • Whole Season Rotational Pesticide System for Integrated Pest Management for Control of Sweetpotato Whitefly in Cotton

      Akey, D. H.; Henneberry, T. J.; Wuertz, D. A.; Silvertooth, Jeff; USDA, ARS, Western Cotton Res. Lab., Phoenix, 85040; Sundance Farms, Coolidge, AZ 85228 (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      A season long pesticide rotational system for cotton management of Bemisia tabaci (Gennadius) (SPWF) was put in place. The system tried to minimize pesticide impact on midseason build -up of beneficials against SPWF. SPWF thresholds were used to begin use of "potent, efficient" insecticides to stop exponential increase of SPWF in late season. Insecticide class rotation was a key element of the system to prevent insecticide resistance. Comparisons between test blocks and best agricultural practices for rest of field showed that SPWF eggs and large immature of September populations, yields (2.68 bales /Ac), and beneficials were about the same among the blocks. The cotton was free of stickiness in the entire field.
    • A Comparison of Three Cotton Tillage Systems: Six Year Summary

      Coates, Wayne E.; Thacker, Gary W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Two reduced cotton tillage systems, both of which utilize controlled traffic farming techniques, were compared to a conventional tillage system in terms of energy requirements, field work time requirements, crop yield, and operating costs. Six seasons of testing show the Sundance system to have the lowest energy requirement of 31.95 Hp- Hr /Ac, the Uprooter -Shredder-Mulcher the second lowest at 47.16 Hp- Hr /Ac, and conventional tillage the highest at 66.89 Hp- Hr /Ac. Field work times of the two reduced tillage systems were about 58% that of conventional tillage. Costs of the two reduced tillage systems are lower than for conventional tillage. We have never measured a significantly lower lint yield with either of the two reduced tillage systems, relative to conventional tillage.
    • The Effect of Night Temperature on Cotton Reproductive Development

      Zeiher, Carolyn A.; Brown, Paul W.; Silvertooth, Jeffrey C.; Matumba, Nkonko; Mitton, Nancy; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      A field study was initiated in the summer of 1993 to investigate the effect of increased night temperatures on cotton reproductive development. DPL 5415 was planted on May 10. Treatments consisted of two temperature regimes placed in a completely randomized design with four replications. The two temperature treatments were initiated at first bloom and treatments terminated after 6 weeks. Cotton grown under ambient night temperature served as the control treatments while plants where the infrared radiation balance was modified to increase the nighttime foliage temperature served as the high night temperature treatment. This study showed that increasing the nighttime foliage temperature of cotton reduced vegetative dry matter production, plant height, and fruit retention. The photosynthetic capacity of the two treatments was not significantly different, suggesting that increased respiration at these higher nighttime foliage temperatures may be responsible for the reduction in assimilated carbon which contributed to the poor fruit retention.
    • The 1994 Arizona Cotton Advisory Program

      Brown, P.; Russell, B.; Silvertooth, J.; Ellsworth, P.; Stedman, S.; Thacker, G.; Hood, L.; Husman, S.; Cluff, R.; Howell, D.; et al. (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      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 (fax only in Yuma County only) from the local county extension office or by computer from the AZMET computer bulletin board.
    • Influence of Pink Bollworm, Pectinophora Gossypiella, (Saunders) (Lepidoptera : Gelechiidae), Female Age on Oviposition Capacity and Egg Hatchability

      El-Lissy, O.; Al-Beltagy, A.; Antilla, L.; Leggett, J. E.; Silvertooth, Jeff; Arizona Cotton Research and Protection Council, Tempe, AZ; Plant Protection Research Institute, Cairo, Egypt; USDA -ARS- Western Cotton Research Laboratory, Phoenix, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Oviposition capability and e 4: hatchability of three laboratory reared strains of pink bollworm, Pectinophora gossvpiella, (Saunders) were evaluated to determine the effect of age on the female reproductive capacity. From comparisons of various female ages in terms of the amount of eggs deposited and the level of ex hatchability, it was concluded that young females (3-6 days old) had the highest potential for oviposition and that their eggs had the highest percentages of hatchability.