• Cauliflower Variety Trials, 1989/1990

      Butler, Marvin; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Cantaloupe Variety Trial, 1990

      Butler, Marvin; Mayberry, Keith; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Evaluation of Biological Insecticides for Control of Beet Armyworm in Lettuce

      Palumbo, John C.; Butler, Marvin D.; Mullis, Clayton H. Jr.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
      A field study was conducted at Yuma in 1990 to examine the efficacy of several biological insecticide formulations on beet armyworm in seedling lettuce. After a single application at thinning, none of the insecticides adequately reduced larval populations below damaging levels. Reductions in plant stand by larvalfeeding were significantly lower in plots treated with Lannate, Javelin, Biobit and Dipel. Lettuce seedling densities were reduced greaterthan 80% in untreated plots.
    • Effect of Nitrification Inhibitors on Nitrogen Utilization Efficiency in Sweet Corn

      Doerge, Thomas A.; Tucker, T. C.; McCreary, T. W.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
      A field experiment using subsurface drip irrigation was conducted at the Maricopa Agricultural Center on a Casa Grande sandy loam soil to evaluate the effect of varying nitrogen (N) sources on the growth and yield of 'Sweetie' 82' sweet corn when applied with, and without four nitrification inhibitors (Nl). The NI treatments included nitrapyrin (N-Serve*), dicyandiamide (DCD), ammonium thiosulfate, and N-Hib Calcium™. Nitrogen was supplied as urea -ammonium nitrate (UAN -32). In addition, an all nitrate source plus a control which received no added N were used. Al! N treated plots received a total of 111 lbs. N acre in split applications at the V3, V6 and the V12 stages. All solutions were applied through buried, perforated PVC tubing to simulate application through the buried drip irrigation system. The inclusion of the nitrification inhibitors with UAN-32 had no significant effect on marketable ear yield, total N uptake or nitrogen use efficiency.
    • Effectiveness of Pesticides with Novel Chemistries Against Different Life Stages of the Sweet Potato Whitefly

      Byrne, David N.; Draeger, Erich A.; Meade, Donna L.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
      The sweet potato whitefly is an insect whose economic importance is continually expanding as it becomes a more efficient vector, increases its fecundity and broadens its host range. To keep pace with its ability to develop resistance to existing classes of pesticides, we have undertaken a program to examine the effectiveness of pesticides with novel chemistries and novel modes of action. Several have shown themselves to be very effective against the various life stages of the sweet potato whitefly. Once these are incorporated in to our arsenal of pesticides, we hope to be able to manage resistance by prudently using these new materials.
    • Poast/Lettuce Trial

      Butler, Marvin; Heathman, Stan; Oebker, Norman F.; Bantlin, Marguerite; Yuma Valley Agricultural Center (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • International Asparagus Cultivar Trial

      McGrady, John; Tilt, Phil; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Sustainable Lettuce Production

      McGrady, John; Matheron, Michael; Palumbo, John; Rethwisch, Michael; Butler, Marvin; Matejka, Joe; Tilt, Phil; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Watermelon Variety Trial, 1990

      Butler, Marvin; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Comparison of Different Fungicides for Control of Downy Mildew of Broccoli -- 1991 Field Trial

      Matheron, M. E.; Matejka, J. C.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
      Downy mildew of broccoli, caused by the plant pathogenic fungus Peronospora parasítica, can be found every year in many broccoli fields in Arizona. The severity of the disease is affected by the occurrence and duration of weather conditions favorable for disease development. During the 1990-91 vegetable season in western Arizona, different fungicides and rates of materials were evaluated in the field for disease control. Ridomil /Bravo and Bravo, which are currently registered for use on broccoli to control downy mildew, and Aliette, which is currently not registered for use on this crop, provided significant disease control compared to untreated plants. Rovral and Topcop did not control downy mildew on broccoli.
    • Broccoli Variety Trials, 1989/1990

      Butler, Marvin; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Effect of Fungicides Applied at Different Rates on Control of Sclerotinia Leaf Drop of Lettuce -- 1990 Field Test

      Matheron, M. E.; Matejka, J. C.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
      Leaf drop of lettuce, caused by the plant pathogenic fungi Sclerotinia sclerotiorum and S. minor, is found every year in some lettuce fields in Arizona. When environmental conditions are favorable, disease incidence and resulting crop loss can be significant. During the 1989 -90 lettuce season in western Arizona, different fungicides and rates of materials were evaluated in the field for disease control Ronilan and Rovral, the two fungicides currently registered for use on lettuce for control of Sclerotinia leaf drop, provided significant disease suppression and increased yields at all rates tested. Bravo and Botran did not control the disease.
    • Harvest Season Effects on Asparagus Yield

      McGrady, John; Tilt, Phil; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Stand Establishment of Lettuce Seed Produced in Different Seasons

      Mnichowicz, P.; Coons, J.; McGrady, J.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Nitrogen and Water Effects on Yield, Quality and Tissue Nitrate Concentration in Subsurface Trickle Irrigated Melons

      Pier, J. W.; Doerge, T. A.; Stroehlein, J. L.; McCreary, T.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
      Rising water costs and concern for groundwater contamination are encouraging growers to improve irrigation and fertilization efficiency. The objectives of this study were to determine water and fertilizer nitrogen (N) rates leading to optimum yield and harvest quality and to develop a plant tissue test to aid in melon nitrogen fertilization. In 1990, a field experiment consisting of a complete 3x3 factorial arrangement of optimum, sub- and super-optimum rates of urea ammonium- nitrate and water applied through a subsurface trickle irrigation system to cantaloupe, honeyloupe and watermelon was conducted at the Maricopa Agricultural Center. Petioles were sampled from the youngest mature leaf beginning at the early runner stage and then weekly until first harvest. Petiole nitrate concentrations were determined using a high pressure liquid ion chromatograph. Harvested melons were weighed and graded for marketability and soluble solids were determined. Petiole nitrate levels were highly responsive to N fertilizer treatments and accurately quantified visual observations of crop N status. Petiole nitrate results also indicated that later fertilizer split applications occurred after the point of maximum plant uptake. Tensiometer readings suggested that the highest rate of water application led to deep percolation and nitrate leaching where nitrogen fertilizer was excessive. Watermelon showed the clearest yield response to the water and nitrogen treatments. Honeyloupe responded well to high water but poorly to higher nitrogen application rates. Cantaloupe yields responded best to higher nitrogen and medium water levels.
    • Canola Growth Reponse to Different Rates of Irrigation Regimes

      Harper, Frederick C.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Kerb/Lettuce Variety Trial, 1989/1990

      Butler, Marvin; Oebker, Norman F.; Bantlin, Marguerite; Yuma Valley Agricultural Center (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Broccoli Downy Mildew Tolerance Trials

      Butler, Marvin; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
    • Water Stress-Induced Osmotic Adjustment in Expanding Leaves of Tepary Bean )Phaseolus actifolins, Gray) Seedlings

      Al-Akel, Saleh; Bartels, Paul G.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)
      Tepary beans perform better than common beans under drought conditions. The mechanism of drought tolerance in tepary bean seedlings was explored by determining the water potential, osmotic potentia4 relative water content and level of free sugars and concentration of K ions within expanding leaves. Two week old seedlings were subjected to a gradual water stress with sorbitol solutions exhibiting OP values of -0.19 MPa and -0.47 MPa. Tugor remained constant whereas WP, OP and RWC declined following the stress treatment. Osmotic adjustment (0.4) occurred in each treatment but the contribution of sucrose and fructose to OA was minor. Some sorbitol was translocated to leaves and contributed to OA. The K ions did not contribute to the OA. A significant decrease in cell size was observed
    • Cultural Alternative for Avoidance of Lettuce Infectious Yellows Virus (LIYV)

      McGrady, John; Rubatzky, Vince; Oebker, Norm; Hartz, Tim; Butler, Marvin; Tilt, Phil; Hagerman, Sherry; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1991-05)