• Effects of Sodium Chloride on Tepary Bean

      Alislail, Nabeel Y.; Bartels, Paul G.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      Osmotic adjustment is one of the adaptive responses of plant species to salinity, In tepary bean seedlings, salinity led to osmotic adjustment in different parts of the seedlings. The osmotic potential of the leaves increased to 340rnM(-1MPa)in seedlings treated with - 0.75 MPa NaCl. Water and osmotic potential of leaves and proximal parr of the roots were more negative than the controls whereas the turgor potential remained about the same. The osmotic adjustment of the tepary bean may result from the synthesis and accumulation of free sugars and amino acids or the accumulation of inorganic ions within the tissue. A quantitative analysis of the sugars and amino acids from salt stress treated tepary bean seedlings showed that they would contribute only -0.15 MPa to the osmotic adjustment whereas inorganic ions would contribute -0.45 MPa. The sum of these osmotic potentials is -0.6 MPa which is -0.4 MPa short of the observed osmotic values. These results suggest that additional substances also contribute to the osmotic adjustment of tepary beans.
    • Tolerance of Lettuce to Salts in Irrigation Water

      Coons, J.; Mendlinger, S.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Control of Liriomyza trifolii in Head Lettuce

      Rethwisch, Michael D.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Thrips Control on Onions

      Rethwisch, Michael D.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Control of Liriomyza trifolii in Celery

      Rethwisch, Michael D.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Examination of the Expansion of the Host Range of the Sweet Potato Whitefly

      Byrne, David N.; Miller, William B.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      A Florida strain of sweet potato whitefly, Bemisia tabaci (Gennadius), was found to have an expanded range which includes several new food crops. To determine why, we examined how it processes plant nutrients. The amino acid and carbohydrate content of phloem sap from poinsettia and pumpkin and of honeydew produced by the Florida strain were analyzed Honeydews produced by a strain from Arizona feeding on both plants were also analyzed Poinsettia phloem sap contained 15 amino acids; 14 of these were in pumpkin phloem sap. Almost all the same amino acids were in the honeydews produced by the two strains on the two hosts. Carbohydrates in phloem sap and honeydew were common transport sugars, like sucrose. Both honeydews contained trahalulose, a disaccharide not previously associated with insects. Both strains processed phloem sap and honeydew from both plants in the same manner, but the Florida strain produced significantly larger quantities of honeydew; it is therefore assumed to process more phloem sap. Since this strain has access to more phloem sap it also has access to more of the amino acids, which are in short supply in the phloem sap of some plants, allowing it to broaden its range.
    • Whitefly-Transmitted Geminiviruses of Tomato and Pepper in Arizona and Their Relationship to Geminiviruses in Florida and in Mexico

      Brown, J. K.; Poulos, B. T.; Nelson, M. R.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Slowing Spread of Lettuce Infectious Yellows Virus with Stylet Oil

      Nelson, Merritt; Stowell, Larry J.; Orum, Tom; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      Infection by lettuce infectious yellows vines was reduced in lettuce treated with stylet oil. There was a difference in the final infection level between treated and untreated blocks and reduced infection in early readings. Yields were slightly better in the treated blocks. It has not been determined if and under what conditions it would be feasible to use this treatment on a practical scale.
    • Analyses of Virus Disease Management Programs

      Nelson, Merritt; Stowell, Larry J.; Orum, Tom; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Powdery Mildew of Cantaloupe - Testing New Fungicides for Disease Control

      Matheron, M. E.; Matejka, J. C.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      Powdery mildew of cantaloupe, caused by the fungus Sphaerotheca fuliinea, is a perennial and often serious disease in Arizona. In 1989, potential new fungicides were evaluated for disease control in a field trial. All tested materials provided significant control when compared to untreated plants. Of the compounds tested only Bayleton currently is registered for use on cantaloupe. Rally, which performed extremely well in this test; should be available for use on cantaloupe in the near future.
    • Sclerotinia Leaf Drop of Lettuce - Testing New Fungicides and Formulations of Ronilan for Disease Control

      Matheron, M. E.; Matejka, J. C.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      Leaf drop of lettuce, caused by the fungus Sclerotinia sclerotionunb is a sporadic but potentially destructive disease in Arizona During the 1988-89 lettuce season in western Arizona, different fungicides and formulations of materials were evaluated in the field for disease control. All tested compounds provided significant disease suppression and increased yields, provided that a sufficient rate of fungicide was applied. Ronilan and Rovral, the two fungicides currently registered for use on lettuce for Sclerotinia leaf drop, were the most effective fungicides in this test, performing significantly better than the two experimental materials. The SODF formulation of Ronilan provided significantly better disease control than the SOW formulation of the same compound.
    • Down Mildew of Broccoli - Effect of Fungicides on Disease Control and Crop Yield

      Matheron, M. E.; Matejka, J. C.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      Downy mildew of broccoli, caused by the fungus peronowora parasitica, usually can be found on a yearly basis in broccoli fields in Arizona During the 1988-89 season, four different fungicides were evaluated in the field for disease control. All four materials significantly reduced the number of downy mildew lesions on treated broccoli leaves. Although significant disease control was achieved the average head weight was not significantly different when treated plants were compared with untreated plants. Light to moderate levels of downy mildew or late development of disease, as found in this trial, apparently do not require application of fungicides to prevent yield loss. Ridomil/Bravo and Bravo currently are registered for disease control, while SDS-59891 and Aliette are not registered for use on this crop.
    • Lettuce Tipburn Studies in Arizona

      Oebker, Norm; Ryder, Ed; Harper, Fred; White, Marcia; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • A Preliminary Report on Asparagus Harvest Duration Effects on Storage Carbohydrates and Yield

      McGrady, John; Tilt, Phil; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Effects of Nitrogen Rates on Yields and Quality of Watermelon, Cantaloupe and Honeyloup

      Stroehlein, J. L.; Pier, J.; Tucker, T. C.; Doerge, T. A.; McCreary, T. W.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      A study was made of the response of six kinds of melons to different nitrogen fertilizer rates when grown with drip irrigation. Results indicated a general response of petiole nitrate and yields to increasing N rates, depending on the kind of melon. The study will be continued in 1990 and include water and N rates with three kinds of melons.
    • Effects of Nitrogen and Water Rates on Nitrogen Uptake Dynamics in Drip Irrigated Sweet Corn

      Doerge, T. A.; Stroehlein, J. L.; Tucker, T. C.; Fangmeier, D. D.; Oebker, N. F.; McCreary, T. W.; Husman, S. H.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      A complete factorial experiment using three nitrogen (67, 156 and 245 lbs N/acre) and three water rates (70, 100 and 130% consumptive use) examined the specific management criteria necessary for obtaining optimum yield and quality of drip- irrigated 'Sweetie '82' sweet corn. The crop was planted on 22 February and harvested on 30 May with an 86/50° F heat unit accumulation of 1444. When present, a nitrogen deficiency greatly decreased marketable yield number of marketable ears/plant mean ear weight, ear length and tip fill. Higher moisture rates generally had less effect on yield and quality than did N rates; however, increasing water rates significantly increased marketable yields and plant height. The effect of N and water rates on N and dry matter accumulation and on diagnostic plant tissue testing results for sweet corn are also presented The maximum marketable yield obtained in this experiment was 7.2 tons per acre, using 245 lbs N/acre and 20.5 inches of irrigation water.
    • Sustainable Vegetable Production with Modified Cultural Management

      McGrady, John; Butler, Marvin; Matheson, Michael; Rethwisch, Michael; Matejka, Joe; Tilt, Phil; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Sweet Corn Irrigation Scheduling Using Infrared Thermometers and the Crop Water Stress Index

      Husman, Stephen H.; Garrot, Donald J. Jr.; Fangmeier, Delmar D.; Oebker, Norman F.; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
      The Crop Water Stress Index (CWSI) was used to schedule irrigations on Jubilee sweet corn on 12 drip- irrigated plots at the Campus Agricultural Center in Tucson. Irrigations were to be scheduled at 0.15, 0.35, and 0.50 CWSI values to represent a wet, medium and a dry treatment. Actual average CWSI values at time of irrigation were for 0.14, 0.36, and 0.48. There were no significant yield or quality differences for the wet and medium treatments with exception of a greater ear diameter in the wet treatment. Yield and quality significantly decreased for the dry treatment scheduled at a CWSI value of 0.48. Irrigation application totals were 26.4, 24.2 and 18.3 inches for the wet, medium and dry treatments respectively.
    • Sweet Corn Cultivar Trials at Maricopa Agricultural Center, 1989

      Oebker, Norm; Harper, Fred; Gibson, Rick; White, Marcia; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)
    • Watermelon Variety Trial, 1989

      Butler, Marvin; Oebker, Norm; Oebker, Norman F.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-05)