• 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • 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.
    • Practical Uses of Crop Monitoring for Arizona Cotton

      Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
    • Nitrogen, Phosphorus, and Potassium Uptake by Upland and Pima Cotton

      Unruh, 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 nitrogen (N), phosphorus (P), and potassium (K) uptake by Upland cotton (Gossypium 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 N, P, and K uptake and the partitioning of each nutrient 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. The appropriate analyses for total N, P, and K were determined on each fraction (except lint). 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 total nutrient uptake and partitioning within both Upland and Pima cotton. In every case there was close agreement between the predicted and actual total nutrient uptake. For Upland cotton the actual total N, P, and K uptake was 199, 29, and 250 kg ha⁻¹ and the predicted total N, P, and K uptake was 199, 29, and 255 kg ha⁻¹, respectively. For Pima cotton the actual total N, P, and K uptake was 196, 29, and 215 kg ha⁻¹ and the predicted was 210, 29, and 229 kg ha⁻¹, respectively. The pattern of nutrient partitioning in Upland cotton were similar to the findings of others and Pima showed the same general patterns of partitioning as Upland cotton. Seeds were a major sink of nutrients. Nutrient uptake in seeds resulted in decreasing uptake in leaves and stems. Presumably, due to mobilization of nutrients from those parts to the seeds during seed development. The nutrient requirements to produce 100 kg lint ha' for Upland cotton was 15, 2.2, and 19 kg ha⁻¹ for N, P, and K, respectively and was 20, 3.0, and 22 kg ha⁻¹, respectively for Pima cotton.
    • Boll Maturity Estimates for Mid- and Late-Season Flowering Dates in Arizona

      Brown, P. W.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Boll maturity dates and the number of days after flowering for a boll to reach physiological maturity were estimated for six representative flower dates: 15 July, 29 July, 12 August, 26 August, 9 September and 23 September. Estimates were developed for 28 locations using historical heat unit (HU) information using the assumption that 600 HUs are required after flowering for a boll to reach physiological maturity. The results are presented in both tabular and graphical forms.
    • Defoliation Research on Pima and Upland Cotton at the Maricopa Agricultural Center in 1993

      Nelson, J. M.; Hart, G.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Field studies were conducted at the Maricopa Agricultural Center to evaluate the effectiveness of selected defoliation treatments on Pima and upland cotton under warm and cool weather conditions. Weather conditions during September tests were warm and dry while in late October tests weather was very cool. Defoliation treatments resulted in a high percentage of leaf desiccation in a test on 10 September. Ginstar and Dropp + Def treatments gave good defoliation of cotton in a 23 September test. In October tests, defoliation treatments were effective on Pima cotton but upland cotton as difficult to defoliate. Ginstar defoliant was generally as effective as the Dropp + Def treatment at the rates tested.
    • Defoliation Research on Pima and Upland Cotton at the Marana Agricultural Center in 1993

      Nelson, J. M.; Barney, G. F.; Hart, G. L.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      A field study was conducted at the Marana Agricultural Center to evaluate the effectiveness of ground rig applied defoliant treatments on Pima and upland cotton under cool weather condition. The experimental defoliant Ginstar and the combination treatment of Dropp + Def resulted in good defoliation 14 days after application.
    • Validity of the Pinhead Square Treatment Program for Pink Bollworm Suppression and Impact of Several Insecticides on Arthropod Fauna in Cotton

      Ellsworth, Peter C.; Meade, Donna L.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      A limited chemical control tactic known as pinhead square treatment has gained recent Favor as a component of pink bollworm population management. The strategy has economic and ecologic goals of using reduced insecticides early in the season (to include lower rates, half the acreage, and less potent chemistry) in order to reduce later season risk of pink bollworm infestations. This strategy also depends in part on the cultural tactic which results in "suicidal emergence" of overwintering pink bollworms through optimal planting date management. The combination of these tactics has been used in the past to overcome boll weevil populations area-wide. This study is focused on the evaluation of this system as a basis for pink bollworm suppression. Though only preliminary is presented here, it is clear that there are numerous insects impacted by this practice which interact in complex ways to influence pest populations of all kinds. Furthermore, the fate of such a practice in any production system is also influenced by the specific chemical agent used. This experiment details the use of four different classes of insecticide chemistry as well as one bioinsecticide. The experiment has been duplicated in 1993; however, only 1992 data are shown here.
    • Short Staple Cotton Variety Trial, Safford Agricultural Center, 1993

      Clark, L. J.; Carpenter, E. W.; Hart, G. L.; Nelson, J. M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      Fifty three short staple varieties were grown in a replicated field trial on the Safford Agricultural Center. HS SAL 10, a long season variety, was the highest yielding variety in the trial with a lint yield of 1772 pounds per acre. Average yields in this trial were lower than in 1992, even though there were more heat units during the growing season. HVI data for the varieties in the trial are included in this report.
    • The Pegasus Rapid Plowdown System: A New Concept in Cotton Tillage

      Thacker, Gary W.; Coates, Wayne E.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      This new concept in tillage is to open a deep, temporary slot next to the cotton row and to insert the stalks and/or roots into the slot before the soil falls back in. The Pegasus Rapid Plow Down System is a relatively simple implement which offers good residue burial and reliability. Our limited field test data indicate that this invention requires less energy and field work time than conventional tillage systems.
    • Physiological Response of Cotton to Terminal Damage

      Unruh, B. L.; Silvertooth, J. C.; Hanline-Boerum, T. R.; Marlow, B. M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      The terminal of a cotton (Gossypium spp.) plant controls the growth of lower vegetative branches through the production of hormones. If the terminal is damaged then the lower vegetative branches will begin to grow and produce new mainstems. The objective of this study was to determine what delays, if any, are caused by damage to the terminal meristem. Three identical experiments (differing only by their planting date) were conducted in the greenhouse in which Upland (G. hirsutum L., var. DPL 5415) cotton was planted in 24 pots and allowed to grow until the majority of the plants reached the four true -leaf stage. At that point half of the plants had their terminals removed. Twice weekly series of plant measurements were recorded for each plant in the study. Measurements taken included the number of mainstem nodes, plant height, node of the first fruiting branch (FFB), days after terminal removal (DATR) until the appearance of the FFB, node of the first bloom, and DATR until the appearance of the first bloom were recorded. Removal of the terminal significantly increased the node of the FFB, the node of the first bloom, and the occurrence of each of these by 7 to 8 days. Regression analysis was used to model plant height and the accumulation of mainstem nodes as a function of DATR. Results showed that plants with terminals removed did reach the same height as the control group. However, the plants with their terminals removed never accumulated as many mainstem nodes as their counterparts in the control group.
    • Seasonal Distribution of Cotton Leafperforator: Pheromone Dispenser Persistence and Effect of Trap Height on Moth Catches in Pheromone Baited Traps

      Leggett, J. E.; Henneberry, T. J.; White, R. D.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1994-03)
      The cotton leafperforator (CLP) Bucculatrix thurberiella Busck. is a sporadic pest in cotton fields of southwest desert area. The cotton leafperforator sex pheromone was identified and synthesized by Hall et al. (1992), thus providing a sensitive method for detecting CLP moths. Tests were conducted in 1992 and 1993 to determine the effective life of CLP polyethylene pheromone dispensers, correlate CLP male moth catches to cotton field infestations, determine the seasonal distribution, and effect of trap height on moth catches. The polyethylene pheromone dispensers were effective for about 4 weeks. The best correlation coefficients for 1993 data, were obtained by comparing CLP moth catches per night to main stem leaf damage at 6 node position from top of plants at field edges. Horseshoe stage CLP per leaf and trap catches had the highest correlation coefficient, r= 0.78. There was more than twice as much CLP damage to leaves at field edges when compared to leaves 10 m into the field. The first CLP moth capture occurred in early to late July and increased rapidly each year in August to 100 to 200 per trap night, but was variable in September, with a high of 300 and a low of 9 per trap night. CLP- baited delta traps placed 0.3 m above ground caught more moths than traps placed at greater heights from 11 to 21 August.