• Cottonseed Treatment Evaluations in Arizona, 1990

      Silvertooth, J. C.; Malcuit, J. E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Field experiments were conducted at four locations in Arizona (Yuma, Maricopa, Marana, Safford) to evaluate 16 cottonseed treatments on cotton that included 12 on Upland (Q. hirsutum L.) and 4 on Pima (Gossvpium barbadense L.). Stand counts were taken to evaluate the effectiveness of each treatment. Statistical analysis showed no significant differences among the treatments used for the Upland cottonseed. Significant differences were found among the treatments used for the Pima cotton seed at the Marana and Safford locations only.
    • Pima Cotton Improvement

      Turcotte, E. L.; Percy, R. G.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Pima experimental strains P67, P69, P71, P73, P74, and Pima S -6 were grown in Regional tests at 11 locations across the Pima belt in 1990. P73 averaged highest in mean yield across locations followed by P74, P69, P67, Pima S-4 and P71. The experimental strains, in comparison with Pima S-6, had longer, stronger, finer, and more whitish fiber. Experimental strains P45, PSI, P53, P62, P66, and EIS were released jointly by the USDA ARS and the Arizona Agricultural Experimental Station, and registered in Crop Science.
    • Uptake and Reside of 3, 4-Dichloro-5-Isothiazole Carboxylic Acid in Cotton Plants and Soils Under Field Conditions

      Bartels, P. G.; Olvey, J.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      DICA (3, 4-dichloro-5-isothiazole carboxylic acid) is being used as a chemical hybridizing agent in the cotton breeding program of Chembred Seed Company. This compound produces male sterile flowers. Registration of this compound by EPA requires that a plant residue study be conducted to provide data on the quantitative amounts of residues in F₁ plants and seeds, F₂ seeds and in the soil. This study was carried out in Arizona because the hybrid F₂ cotton seeds will be grown in Arizona.
    • Planting Date and Susceptibility to Pink Bollworm

      Brown, P.; Silvertooth, J.; Moore, L.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      The susceptibility of cotton to spring emergence of pink bollworm (PBW) was evaluated for a variety of planting dates in Pinal, Maricopa, LaPaz and Yuma counties using historical climate records and heat - unit -based models that predict PBW emergence and cotton development. Early planted cotton proved most susceptible to the PBW emergence, however, springtime weather conditions also played an important role in determining overall susceptibility. Growers wishing to incorporate planting date as one aspect of PBW management should keep abreast of early season weather conditions.
    • Pima Cotton Genetics

      Percy, R. G.; Turcotte, E. L.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      An isozyme study of the diversity and structure of Goss_vpium nii revealed levels of genetic variation within the species which were high for an island endemic. Infraspecific diversity of G. darwinii was observed among populations of the various Galapagos Islands. Evidence of introgression of other Gossypium species into darwinii was noted. An investigation into the effects of altered Pima (G. barbadense) fiber genotypes on interspecific hybrid fiber characteristics indicated that parent genotype could significantly affect hybrid fiber length, strength, uniformity, and micronaire. However, hybrid heterosis for fiber length and micronaire greatly exceeded the influence of parent genotype. Hybrid fiber characteristics were unique, fitting within neither the extra -long staple nor long staple classifications. A conversion program to convert photoperiodic short-day accessions of a Gossvpium barbadense germplasm collection to day neutrality continues.
    • Short Staple Variety Demonstration, Pinal County, 1990

      Malcuit, J. E.; Stedman, S.; Silvertooth, J. C.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Short staple variety trials were conducted for three years at Prechel Farms near Coolidge At. Six varieties were included in 1988, twelve in 1989, and eight in 1990. Results from the statistical analysis showed significant differences among varieties in each of the three tests. Lint yields ranged from 908 to 1313 lbs. lint acre⁻¹ in 1988, 2844 to 4827 lbs. seedcotton acre⁻¹ in 1989, and 695 to 1059 lbs. lint acre⁻¹ in 1990. Those varieties that were medium to short-season maturity types yielded higher than long season maturity types in the 1988 and 1990 seasons. The reverse was true in the 1989 season.
    • Pink Bollworm Management in Pima and Upland Cottons: Planting Date and Termination Date Effects

      Terry, Irene; Silvertooth, Jeffrey; Summers, Carol; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Different planting and termination dates of Pima S-6 and Upland (Deltapine 90) cotton (Gossypium barbadense L. and hirsutum L. respectively) were tested for their effects on pink bollworm (Pectinophora gossypiella) infestations. Tests were conducted during 1989 and 1990 cotton seasons at the University of Arizona Yuma Valley Agricultural Experiment Station. Planting dates indicated little effect on early season infestations of pink bollworm for either cotton. However. irrigation termination had the greatest effect on late season infestations. In 1989. heat unit (degree day 12.8/30° C. lower and upper thresholds) accumulations were several days earlier than 1990, due to a very warm year. Pheromone trap counts indicated higher populations in 1989 than 1990; however. infestations in the field were similar between the years. Infestations dramatically increased during July through September, indicating that a longer cotton season with actively growing fruit, results in a continued population increase. The termination dates affected the amount of fruiting structures left in the field and thereby affected infestations of overwintering larvae in the field. Termination date had a dramatic effect on the % bolls infested with overwintering larvae and the density of overwintering larvae /m.
    • Nitrogen Management Experiments for Upland and Pima Cotton, 1990

      Silvertooth, J. C.; Clark, L. J.; Malcuit, J. E.; Carpenter, E. W.; Doerge, T. A.; Watson, J. E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Two field experiments were conducted in Arizona in 1990 at two locations ( Maricopa and Safford). 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 fertilirystatus, and crop monitoring to ascertain crop fruiting patterns and crop N needs. Results at both locations 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 in response to the N fertilization regimes used. At Maricopa, fruit retention levels were low, petiole NO₃⁻-N concentrations relatively high, and yield responses to higher and later applications of fertilizerN were negative. At Safford, fruit retention levels were higher, petiole concentrations of NO₃⁻-N reflected strong crop demand, and a positive response to rates of fertilizer N up to 170 lbs. N/acre was measured.
    • Trap Crop Effectiveness in Community Boll Weevil Control Programs

      Moore, Leon; Watson, Theo F.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Trap crops, along with delayed uniform planting and pinhead square treatments, greatly reduced spring populations of overwintered boll weevils, Anthonomus grandis Boheman, in a Laveen. Arizona community -wide 1PM program in 1987. Thirty four trap crops. planted fifteen days ahead of the regular crop. had as many as 39536 damaged plants/ha before insecticide treatments were initiated. Five insecticide applications at 3 day intervals beginning at square initiation were used to destroy weevils before the trap crops were plowed under at the time pinhead square treatments were initiated in regular planted fields. Damaged square infestations were 2 to II times lower throughout the season in 1987 compared to 1986 while average lint yields per ha increased from a low of 941 kg in 1985 to 1345 kg in 1986 and 1506 kg in 1987.
    • Fat Content and Reproductive Condition of Migrating and Dispausing Boll Weevils in South Carolina and Arizona

      Leggett, J. E.; Silvertooth, Jeff; Bantlin, Marguerite; USDA-ARS-Western Cotton Research Laboratory (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Overwintered female boll weevils, Anthonomus grandis Boheman, collected in grandlure- baited traps were significantly leaner than weevils taken from winter habitat. Weevils that emerged from naturally infested cotton bolls tended to be fat as adults regardless of subsequent adult diet, but adult diet can affect gonadal development. Weevils that emerged from bolls in 1975 in South Carolina had a higher winter survival rate and emerged from winter habitat earlier than the total population. Migrant weevils appear to be mainly colonizers that have some body fat and medium size gonads. The physiological condition of migrants was fairly consistent over time and location in South Carolina but not in Arizona. The time of migratory flight was related mainly to plant maturity and population levels in South Carolina. Weevils collected from cotton plants in South Carolina and Arizona had significantly more body fat than weevils trapped at the cotton field but oogenesis was variable between the two locations.
    • Defoliation of Pima Cotton, 1990

      Silvertooth, J. C.; Husman, S. H.; Thacker, G. W.; Howell, D. R.; Winans, S. S.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Five field experiments were carried out in several representative cotton producing areas of Arizona to evaluate the effectiveness of a number of defoliation treatments on Pima cotton. Variable conditions were encountered among the experimental locations in 1990 for treatment comparisons. However, it appears that consistencies in the effectiveness of several treatments for Pima defoliation offer a basis for recommendations across the state.
    • Short Staple Variety Trial, Cochise County, 1990

      Clark, Lee J.; Schwennesen, Eric; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Seven New Mexico acala varieties and one non-acala short staple variety were evaluated for yield and other agronomic variables. 1517-88 produced the most seed cotton but HS 46, the non-acala produced slightly more lint. Both varieties yielded slightly less than three bales of lint per acre. Yields of most of the varieties in the trial were 100 to 200 pounds less than in the previous year. It is felt that the yield reductions were probably more due to lack of heat units during the growing season than the heat spell in June.
    • Defoliation Research on Pima Cotton at the Marana Agricultural Center in 1990

      Nelson, J. M.; Silvertooth, J. C.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      A field study was conducted at the Marana Agicultural Center to evaluate the effectiveness of selected defoliation treatments on Pima cotton under cool weather conditions. Defoliants were slow acting at this location, probably due to cool night temperatures and dry field conditions. The combination Dropp + Def 6 + Accelerate gave good defoliation results 18 days after application. The experimental defoliant SN 597 NA 243 shows promise as a defoliant for Pima when temperatures are cool.
    • Evaluation of Date of Planting and Irrigation Termination on the Yield of Upland and Pima Cotton

      Silvertooth, J. C.; Watson, T. F.; Terry, L. I.; Malcuit, J. E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Four flea experiments were conducted in 1990 in Arizona to evaluate the response of Upland and Pima cotton to dates of planting and dates of irrigation termination. Planting dates ranged from as early as 27 February in the Yuma Valley (150 ft. elevation) to 8 May at Marana (2,000 ft. elevation). Dates of irrigation termination ranged from 18 July in the Yuma Valley to 8 September at Maricopa and Marana.
    • Aflatoxin Contamination: Variability and Management

      Cotty, Peter J.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Mapping aflatoxin contamination in the field reveals that most toxin occurs in relatively few, highly contaminated, bolls. Several studies suggest that protection of early bolls from pink bollworm damage will eliminate many of these highly contaminated bolls. Early harvest will also help reduce aflatoxin contamination. However, the crop must still be carefully managed after harvest because toxin content of mature bolls can increase very rapidly.
    • Susceptibility of Field Populations of Pink Bollworm (Lepidoptera: Gelechiidae) to Azinphosmethyl and Permethrin

      Osman, Abdelgadir A.; Watson, Theo F.; Sivasupramaniam, Sakunlala; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Responses of five field -collected populations of the pink bollworm. Pectinophora gossypiella (Saunders). from Arizona and southern California. were compared with those of a standard. susceptible -laboratory strain. Field strains showed less than twofold difference in response to azinphosmethyl at LD₅₀ but had variable levels (1.3- to 18.3-fold) of response to permethrin. Strains from Yuma and Phoenix (Arizona) and Westmoreland (California) had highest levels of resistance to permethrin.
    • Effect of Plant Nitrogen Status on Effectiveness of Defoliants for Short Season Cotton Production

      Nelson, J. M.; Hart, G.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      A field study was conducted at the Maricopa Agricultural Center to determine the influence of nitrogen fertility level on the effectiveness of defoliants for short-season cotton production. Increasing the nitrogen fertility level from 30 to 130 lbs N/A decreased lint yields from 3.2 to 26 bales /A. High residual soil N favored the use of a low N fertility rate. Defoliation treatments were most effective at the 30 lbs. N/A fertility level. Increasing the application rate of Dropp from 0.2 to 0.4 lbs. a.i./A increased the percent defoliation. There was a significant linear decrease in the effectiveness of defoliants as the petiole NO₃-N content increased from 300 to 7000 ppm.
    • Status of Pink Bollworm Resistance to Insecticides in Arizona

      Watson, Theo F.; Kelly, Suzanne E.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      Populations of pink bollworm. Pectinophora gossypiella (Saunders), from Yuma, Casa Grande, Marana and Safford were compared with that of a susceptible laboratory (USDA) strain relative to their susceptibility to permethrin. A limited comparison was made with azinphosmethyl. All field strains were significantly more tolerant to permethrin than was the USDA susceptible strain. A comparison of the USDA and Yuma strains using azinphosmethyl indicated no difference in susceptibility between the laboratory and field strains.
    • Water Stress Effects on Upland Cotton Lint Yields Using Infrared Thermometry to Schedule Irrigations

      Husman, S. H.; Garrot, D. J. Jr.; Moore, M.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      The Crop Water Stress Index (CWSI) was used to schedule irrigation on D + PL 90 cotton on a large scale commercial basis in Waddell, Az. The test consisted of sixteen one acre surface irrigated plots. There were four treatments with four replicates arranged in a randomized complete block design. Highest lint yields were attained when irrigations were scheduled at 0.28 CWSI units.
    • Cotton Lint Qualities of Varieties Grown in Southeastern Arizona, 1989

      Clark, Lee J.; Carpenter, Eddie W.; Silvertooth, Jeff; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991)
      High Volume Instrument (HVI) classing of eighteen cotton varieties grown at several elevations in southeastern Arizona are compared by location in this paper. Data presented herein would indicate that elevation does not affect fiber length nor strength, these factors are more a function of variety and management. Micronaire values were seen to be lower at the higher elevations and this was felt to be a function of lower maturity level because of reduced growing season coupled with production of fine fibered New Mexico acalas. This report also contains HVI values on lint from 47 varieties of short staple cotton grown on the Safford Agricultural Center during the 1989 season.