• The Effect of Soil Temperature and Inoculum Levels of Thielaviopsis basicola on Black Root Rot of Cotton

      Hine, R. B.; Mauk, P. A.; Tedla, Tesfaye (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Two planting dates, March 28, and April 28 were used to study the effect of soil temperature during planting on black root rot of cotton. Also, several cotton varieties were evaluated for response to the disease under varying soil temperatures and inoculum levels.
    • Natural Resistance of Cotton to Cotton Leaf Crumple Virus

      Wilson, F. Douglas; Brown, Judith K.; Butler, G. D. Jr. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Cultivars and germplasm lines of cotton, Gossvpium hirsutum L., differed in response to infection by the cotton leaf crumple virus (CLCV). The most widely grown cultivars in Arizona and southern California, 'Deltapine 90' and 'Deltapine 61', are susceptible, while ' Cedix', developed in El Salvador, and 'Coral', developed in Nicaragua, are highly resistant or immune. Nineteen other lines from a resistance breeding project in Nicaragua showed highly variable responses.
    • Nematocide Use for Control of Rootknot Nematodes

      Farr, Charles (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Injection of Telone II in sandy loams containing more than 60 percent sand increased Pima S-6 yield 493 pounds of lint but failed to give economic response with DP 77 in second year cotton. Treatment with Vapam at two rates at the same locations did not increase yield significantly in 1987.
    • Resistance to Verticillium Wilt by Eight Varieties of Short Staple Cotton, Safford Agricultural Center, 1987

      Clark, Lee J.; Hine, Richard B.; Carpenter, Eddie W. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Eight short staple varieties were evaluated for severity of symptoms, percent of plants infected and yield while being grown in a Verticillium nursery on the Safford Agricultural Center. Delta Pine 90 showed the least severe symptoms, had the least number of infected plants and also yielded the highest. Another Delta Pine variety, DP 77, showed moderate symptoms and a 96% infection rate, but it still managed to come in third in yield, only 49 pounds per acre behind DP 90. Yield potential and varietal adaptability must be considered along with Verticillium wilt resistance in deciding what variety to plant, even in a field infested with Verticillium.
    • Response of Texas Root Rot to a Soil Sterilant in Graham County, Part II, 1987

      Clark, Lee J.; Cluff, Ronald E. (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Residual effects from methyl bromide applied in 1986 showed increased yields in 1987. Increases from 115 to 281 pounds of lint per acre were observed, depending on the rate applied in 1986. This residual effect increases the possibility that this soil sterilant will be a useful tool to combat Texas root rot. Differences were also noted between 1986 and 1987 applications.
    • Response of Texas Root Rot to a Soil Sterilant in Marana in 1987

      Thacker, Gary; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Methyl bromidelchloropicrin, a soil sterilant, was deep-injected into cotton beds ten days before planting. Within the kill areas of the Texas Root Rot, the soil sterilant had some significant effects on the mortality and yield of the cotton.
    • Weather Conditions Associated with the Development of Southwestern Rust on Cotton

      Young, Deborah; Brown, Paul (College of Agriculture, University of Arizona (Tucson, AZ), 1988-03)
      Weather conditions leading to the development of southwestern rust on cotton were evaluated at 3 locations in southeastern Arizona. Rust appeared following an extended period of wet, humid weather. In excess of 16 hours of wet canopy/high humidity conditions were observed on two consecutive days between 5 and 7 days prior to the appearance of rust. Temperatures during the wet canopy/high humidity periods were moderate, ranging from 65 F to 76 F. Afternoon rain showers initiated these extended periods of wet canopy /high humidity conditions.