• 1991 Virus Survey of Cantaloupe in Yuma

      Butler, Marvin; Brooks, Dave; Watson, Mike; Oebker, Norman F.; University of Arizona; Pasquinelli Produce (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Broccoli Downy Mildew Tolerance Trial, 1990/1991

      Butler, Marvin; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Broccoli Variety Trials 1990/1991

      Butler, Marvin; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Cantaloupe Variety Trial, 1991

      Butler, Marvin; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Cauliflower Variety Trials 1990/1991

      Butler, Marvin; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Comparative Effectiveness of Bacillus thuringiensis Formulations Against Lepidopterous Pests of Fall Lettuce

      Palumbo, J. C.; Mullis, C. H. Jr.; Reyes, F. J.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      A field study was conducted at Yuma in 1991 to examine the relative effectiveness of several formulations of Bacillus thuringiensis on beet armyworm and cabbage looper on seedling and pre-cupping lettuce. Several applications were made before and after thinning. Results of the study suggest that most formulations are capable of controlling small larvae. However, because of the inherent variation in beet armyworm dispersion, it was difficult to statistically attribute differences in pest levels due to insecticide efficacy.
    • Comparison of Capture, Capture and Thiodan, Malathion and Pounce Insecticides for Control of Two Aphid Species on Broccoli Seed

      Rethwisch, Michael D.; McDaniel, Charles W.; Major, Gary; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Control of Thrips in Seed Onions and Resultant Seed Yields

      Rethwisch, Michael D.; Daily, Bill; Sanderson, David; McDaniel, Charles; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      Four insecticides were evaluated for their effect on onion seed production in Yuma County where two species on thrips (western flower and onion) were present in seed fields. Visual differences between treatments resultant from onion thrips damage was evident within 10 days after treatments were applied at flower opening. Lorsban, Ammo and Capture treatments provided control of onion thrips based on condition of seed heads. Only Ammo and Capture treatments increased seed yield as the Lorsban treatment was thought to repel bees which are needed for pollination. Pyrethroid treatments yielded 40% more than the untreated check. Damage from onion thrips to onion seed in Yuma County is conservatively calculated to currently be at least $1.1 million annually.
    • A Critical Examination of Flight by the Sweet Potato Whitefly

      Blackmer, Jacquelyn L.; Byrne, David N.; Rathman, Robin J.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      In the past we have assumed that sweet potato whiteflies, Bemisia tabaci (Gennadius), were poor fliers with a limited ability to disperse. This assumption was based on the fact that sweet potato whiteflies are extremely small insects (24 -44 μg) and consequently would be subject to desiccation. We also thought small size would limit their capacity to store sufficient energy reserves to sustain flight for long periods of time. Recent experiments have indicated we were wrong on several counts. Data collected in the laboratory using a vertical flight chamber have revealed a number of interesting facts. Of importance is the fact that a portion of the population is capable of sustaining flight for more than 2.5 hours. In a wind-aided situation, this means they can be moved more than 25 miles in a 10 mph wind. Other details of flight behavior are being made clear to us. For example, we found that flight activity is influenced by host plant quality and age of the whitefly. We hope to eventually be able to predict when whiteflies are going to migrate between crops. This will allow growers to make informed decisions concerning planting dates. We are also working in the field to confirm laboratory results.
    • Dry Matter Partitioning of Cowpea (Vigna Unguiculata (L.) Walp.) Under Water Deficit Conditions

      Neto, Manoel C.; Bartels, Paul G.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      Water Stress caused reduction of seed yield in cowpea plants by decreasing total biomass and photosynthesis. The source leaf, pod and seed water potential of stressed cowpea were lower than water potential in non-stressed plants. No differences in water potential and turgor were observed between pod walls and seed of cowpea plants. Partitioning of the total above ground dry matter was similar for both stressed and nonstressed cowpea plants. Photosynthetic rates of single leaves from cowpea were greater for nonstressed than stressed plants. The duration of seed growth of cowpea was not different between stressed and nonstressed plants; however, rate of seed growth at the end of seed filling period was greater in nonstressed plants. Seed growth rate of both stressed and nonstressed cowpea plants declined at about the same time photosynthesis of the source leaf declined. Leaf area index was greatest in nonstressed cowpea.
    • Effect of Insecticides on Sweetpotato Whitefly Numbers and Growth of Broccoli

      Rethwisch, Michael D.; McDaniel, Charles W.; Shaw, Mary; Theissen, James; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      Eleven treatments were applied for sweetpotato whitefly B- biotype control. Best control (62.4%) was evidenced by the Ambush + Thiodan treatment, which had fewest nymph numbers 8 days post treatment and had larger plant sizes (46.3%) 14 days post treatment than the untreated check. Plants in plots receiving treatments including Thiodan and/or Lorsban were also at least 20% larger than the untreated check. Fewest number of adult whiteflies two days post treatments were noted in the Thiodan + M-Pede treatment. Certain treatments increased whitefly numbers.
    • Effect of Oil Treatments on Head Lettuce Photosynthesis and Growth

      Rethwisch, Michael D.; McGrady, John; Main, Greg; Coates, Wayne; Meadows, Mike; McDaniel, Charles; Shaw, Mary; Thiessen, James; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Effect of Oils and an Insecticide Applies to Snap Beans on Leafminer and Associated Parasitoid Numbers

      Rethwisch, Michael D.; Meadows, Michael; Hood, Larry; Winans, Sherwood; Coates, Wayne; Main, Greg; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Effectiveness of Oils in Water for Leafminer Control in Fall Head Lettuce

      Rethwisch, Michael D.; Hood, Larry; Meadows, Mike; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Effects of Insecticides on Leafminers, Liriomyza spp., and Associated Parasitoids on Spring Cantaloupes

      Palumbo, J. C.; Mullis, C. H. Jr.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      A study was conducted to determine the effects of repeated insecticide applications on leaf niner and parasitoid populations on spring melons. After four applications, none of the insecticides induced large build-ups of leafminer larvae. A new material, AC 303630, was very effective in maintaining low numbers of pupae. However, the results of this preliminary test indicate that all insecticides tested had a negative impact on the parasitoid population. In general, in the absence of insectcides, parasitoids were capable of maintaining L. sativae populations at low levels in the experimental plots.
    • Effects of Lettuce Insecticides Applied at Planting

      Rethwisch, Michael D.; Meadows, Michael; Hagerman, Shari; Thiessen, James; McGrady, John; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Evaluation of Agri-Mek with Various Oils and Adjuvents for Control of Leafminers in Spring Head Lettuce

      Rethwisch, Michael D.; Meadows, Michael; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
    • Evaluation of Imidacloprid (NTN 33893) for Control of Aphids on Broccoli

      Palumbo, J. C.; Mullis, C. H. Jr.; Reyes, F. J.; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      The new insecticide Imidacloprid (NTN 33893), which is currently being developed for use on vegetable crops, was evaluated on broccoli for control of aphid species. Studies conducted in the spring of 1991 showed that this material applied postemergence as a granular formulation was extremely effective in preventing aphid colonization throughout the season. Aphid control and broccoli yields were significantly greater in plots treated with Imidacloprid. Due to low numbers of aphids in 1992, we were unable to detect differences in aphid numbers between Imidacloprid treatments and the untreated control.
    • Evaluation of Insecticides for Control of the Apache Cicada on Asparagus

      Rethwisch, Michael D.; McDaniel, Charles W.; Thiessen, James; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)
      Five insecticides were evaluated for Apache cicada control in asparagus. Best control was achieved by two unregistered pyrethroid insecticides. The currently registered pyrethroid insecticide in this study (Pounce) was not as effective as Capture or Baythroid. Methomyl Pinnate) applied after the experiment was also very effective in controlling adult Apache cicadas. Di-Syston provided very little control.
    • Evaluation of Oils and Insecticides for Leafminer Control in La Paz County Snap Beans

      Rethwisch, Michael D.; Meadows, Michael; Hood, Larry; Oebker, Norman F. (College of Agriculture, University of Arizona (Tucson, AZ), 1992-12)