• Cotton Leaf Curl Virus, A Threat to Arizona Cotton?

      Nadeem, Athar, 1955-; Xiong, Zhongguo; Nelson, Merritt; Silvertooth, Jeff; Department of Plant Pathology, University of Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      A serious virus disease of cotton in Pakistan is distantly related to cotton leaf crumple in Arizona. It is much more destructive on cotton than leaf crumple, and has never been found in the western hemisphere. Cotton leaf crumple in Arizona causes only modestly damaging midseason infections, while leaf curl, has had a major impact on the crop in Pakistan. Modern transportation and the increasing movement of living plants in global trade has resulted in them recent introduction of a similar disease of another crop to the western hemisphere.
    • 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.
    • The Use of Fungi to Prevent Aflatoxin Contamination of Cottonseed in the Yuma Valley

      Cotty, P. J.; Silvertooth, Jeff; USDA, ARS, Southern Regional Research Center, New Orleans, LA (College of Agriculture, University of Arizona (Tucson, AZ), 1995-03)
      A strain of Aspergillus flavus that does not produce aflatoxins was applied to soils planted with cotton at the Yuma Valley Agricultural Center in order to assess strain ability to competitively exclude aflatoxin producing strains during cotton boll infection and thereby prevent aflatoxin contamination of cottonseed. In both 1989 and 1990, the atoxigenic strain displaced other infecting strains during cotton boll development. Displacement was associated with significant reductions (75% to 82% in 1989, and 99% in 1990) in the quantity of aflatoxins contaminating the crop at maturity. Although frequency of infected locules differed between years, in both years displacement occurred without increases in the amount of developing boll infection. Currently, an Experimental Use Permit is being sought from the EPA for tests on commercial acreage