• Gibberellic Acid Sizing Trial on Table Grapes, 1987

      Butler, Marvin; Rush, Bob; Kilby, Michael W.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-12)
    • Gibberellic Acid Sizing Trial on Table Grapes, 1988

      Butler, Marvin; Rush, Bob; Kilby, Michael W.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-12)
    • Gibberellic Acid Sizing Trial on Table Grapes, 1989

      Butler, Marvin; Rush, Bob; Kilby, Michael W.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-12)
    • Girdling "Fairchild" Mandarins and "Lisbon" Lemons to Improve Fruit Size

      Wright, Glenn C.; Wright, Glenn; Kilby, Mike; Yuma Mesa Agriculture Center, University of Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 2000-10)
      'Fairchild' mandarins in the Phoenix area and 'Lisbon' lemons in Yuma were girdled beginning in November 1996. November, March and May girdling of the mandarins led to the greatest yield the first year, while March and May girdling led to the greatest yield in years 2 and 3. March girdling yield increases were generally due to greater fruit numbers, while in May, yield increases were due to greater fruit numbers and fruit size. Returns per acre suggest that March and or May girdling of mandarins will lead to greater profits for the grower. Like mandarins, lemon yields were greater following November, or November and March girdling after one year of the experiment. However, yields of these trees dropped considerably the second year, and the trees appear to be in an alternate bearing cycle. No lemon girdling treatment appears to be better than the untreated trees after three years.
    • Growing Blackberries in the Low Desert

      Wright, Glenn C.; Wright, Glenn; Kilby, Mike; Department of Plant Sciences, Yuma Mesa Agricultural Center (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      Twenty-five plants of each of ten blackberry cultivars from Arkansas and Texas were established at the Yuma Mesa Agriculture Center in spring 1994. All the Arkansas cultivars died. Of the Texas cultivars, 'Rosborough' and 'Womack' performed the best, followed by 'Grison' and 'Brazos'. Important cultural practices, harvesting practices and potential marketing strategies are discussed
    • Growth of Citrus volkameriana inoculated with AM fungi in moist or periodically dry soils

      Fidelibus, Matthew W.; Martin, Chris A.; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1999-11)
      ‘Volkamer’ lemon (Citrus volkameriana Tan. and Pasq.) seedlings were inoculated with either of five communities of arbuscular mycorrhizal (AM) fungi collected from either citrus orchards in Mesa and Yuma, Arizona or from undisturbed Sonoran or Chihuahuan desert soils. Plants were then grown for four months under low or high irrigation frequency treatments such that soil water tension reached about -0.01 MPa (moist) or -0.06 MPa (periodically dry), respectively. Plants grown in moist substrate had greater shoot mass than plants grown in periodically dry substrate. Plants inoculated with AM fungi from the Yuma orchard soil had significantly less shoot and root mass, higher specific soil respiration rates, and lower photosynthesis rates than plants treated with inoculum from other soils. Plant phosphorus nutrition did not limit growth. These data show that growth of ‘Volkamer’ lemon seedlings can be substantially affected by arbuscular mycorrhizal fungal communities in moist or periodically dry soils.
    • Heat Unit Based Crop Coefficient for Grapefruits Trees

      Hla, A. K.; Martin, E. C.; Waller, P.; Slack, D. C.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 1996-09)
      Using portable sap flow sensors, the onset and volume of sap moving up the branches of grapefruit (Citrus Paradisi Macfadyen) trees was monitored on an hourly basis. Reference evapotranspiration (ETo) data was obtained from The Arizona Meteorological Network (AZMET). Crop evapotranspiration (ETc) was estimated from soil moisture measurements using a neutron probe. The threshold temperature limits were delineated from an evaluation of the hourly sap flow responses to cold winter and extreme summer temperatures. The heat based crop curve was derived from a correlation of the crop coefficients with heat unit over one crop year. The heat based crop coefficients were found to be similar to crop coefficients derived by other researchers.
    • Helicopters and Frost Prevention: A Preliminary Evaluation

      Brown, Paul W.; Kilby, Michael W.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-12)
    • Hydrogen Cyanamide Trial on Table Grapes, 1985/1986

      Butler, Marvin; Kilby, Mike; Rush, Bob; Kilby, Michael W.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-12)
    • Hydrogen Cyanamide Trial, 1984/1985

      Butler, Marvin; Kilby, Mike; Rush, Bob; Kilby, Michael W.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-12)
    • Impact of preplant soil treatments on survival of Phythophthora in citrus soils

      Matheron, Michael; Porchas, Martin; Maurer, Michael; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1999-11)
      Several different approaches are used with respect to land preparation prior to replanting citrus in Arizona. A study was initiated to examine the effect of cultural preplant practices on the survival of Phytophthora in citrus orchard soils. In June, 1998, a 2-gallon volume of soil was collected from eight different sites within a mature lemon planting on a sandy soil in Yuma or a lemon planting on a heavier soil in Mesa, AZ. Each initial sample was pre-tested, found to contain Phytophthora parasitica, then thoroughly mixed and distributed into six 1-qt plastic containers, which were subjected to different environmental and cultural conditions. The soil in each container was tested for the presence of P. parasitica 1, 4 and 9 months after initiation of the study. The preliminary results of this ongoing study are as follows. Detection of P. parasitica was lower in non-irrigated as compared to irrigated soil. P. parasitica was not detected in non-irrigated soil subjected to a mean temperature of 38°C (100° F) for 3 months. During the 9-month period of time, detection of P. parasitica in soil planted to alfalfa was not reduced compared to soil planted to citrus. Of the treatments examined, dry summer fallow may be the most effective method of reducing the population of P. parasitica to below detectable levels; however, these preliminary findings must be validated by additional planned tests.
    • Improving Management and Control of Fungal Diseases Affecting Arizona Citrus

      Matheron, Michael; Maurer, Michael; Porchas, Martin; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 1997-11)
      Experiments were initiated to evaluate chemical disease management tools for Alternaria fruit rot on navel orange and Coniophora brown wood rot on lemon trees, examine the possible effect of branch diameter on development of Coniophora wood rot on lemon trees and continue evaluations of relative resistance of rootstocks to root rot and stem canker development when inoculated with P. citrophthora and P. parasitica. Rovral or Kocide did not significantly reduce the amount of Alternaria fruit rot on navel orange trees occurring in late summer and early autumn when applied during the preceding winter or spring months. Of several chemical treatments tested, only Nectec paste inhibited the development of Coniophora brown wood rot on inoculated lemon branches. The size of wood decay columns on branches 10 mm (0.5 inch) in diameter were significantly smaller than those developing on branches 50-70 mm (2.0-2.75 inches) in diameter. In extensive trials evaluating root rot caused by Phytophthora citrophthora and P. parasitica, some relatively tolerant rootstocks were found among the group of new potential rootstocks as well as currently used rootstocks such as rough lemon, C. macrophylla and Troyer citrange. C. volkameriana was relatively tolerant to the development of root rot by P. citrophthora but demonstrated variable tolerance to P. parasitica. Comprehensive evaluation of stem canker development on citrus rootstocks inoculated with P. citrophthora or P. parasitica revealed that rough lemon is usually highly susceptible to both pathogens, while C. volkameriana was at times less susceptible (more tolerant) than rough lemon to both pathogens. Some of the new potential rootstocks were highly tolerant or resistant to infection of stem tissue by P. citrophthora or P. parasitica.
    • Improving Management and Control of Fungal Diseases Affecting Arizona Citrus Trees, 1997

      Matheron, Michael; Maurer, Michael; Porchas, Martin; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      Studies were conducted to evaluate potential chemical disease management tools for Alternaria fruit rot on navel oranges and Coniophora brown wood rot on lemon trees, to investigate the possible effect of branch diameter on development of Coniophora wood rot on lemon trees and to summarize our evaluations of citrus rootstocks with respect to relative resistance to root rot and stem canker development when challenged with Phytophthora citrophthora and P. parasitica. We were unable to reduce the level of Alternaria fruit rot on navel oranges with single applications of Abound or copper hydroxide following significant rainfall events. Wood decay in lemon branches inoculated with Coniophora eremophila was significantly suppressed by Abound and a thick formulation of sodium tetrathiocarbonate. The degree of Coniophora brown wood rot in lemon branches of different diameters was variable, although the level of disease in 10 mm diameter branches was significantly smaller than the amount of wood decay in 30 mm diameter branches. Root loss due to Phytophthora citrophthora and P. parasitica in Citrus macrophylla, rough lemon, C. volkameriana and Troyer citrange was lower than most of the 36 different rootstocks tested. On the other hand, root loss on Carrizo citrange, C-35 citrange and sour orange was among the higher values of disease recorded. Stem canker development due to both species of Phytophthora on Troyer citrange, Carrizo citrange, sour orange and Citrus macrophylla was lower than most of the 36 rootstocks tested. Stem cankers on rough lemon and Citrus volkameriana were among the higher values of disease recorded.
    • Influence of Nut Cluster Position on the Incidence of Viviparity for the Pecan Cultivars "Western Schley" and "Wichita"

      Gibson, Richard; Kilby, Michael; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      Vivaparity, a significant quality- reducing condition found in pecans grown in warm, temperate climates, was evaluated by location of the pecan nut within the cluster in two varieties, "Wichita " and "Western Schley". Percentage vivaparity was not affected by position.
    • Influence of Rootstocks on Yield and Quality of "Redblush" Grapefruit

      Fallahi, Esmaeil; Rodney, David Ross; McDonald, Herbert (College of Agriculture, University of Arizona (Tucson, AZ), 1986-12)
      The influence of 12 different rootstocks on yield and quality of "Redblush" grapefruit was studied for several years. Rootstocks consisted of: macrophylla, volkameriana, rough lemon, Palestine sweet lime, sour orange, Carrizo citrange, taiwanica, Savage citrange, Citrumelo, Ichang pummelo, Troyer citrange and Cleopatra mandarin. Trees on volkameriana, Palestine sweet lime, rough lemon, and sour orange had higher yield than other rootstocks, while trees on Savage citrange had lowest yield. However, soluble solids and acid /sugar ratio were relatively low in the fruits on volkameriana but high in fruit on Savage citrange rootstocks.
    • Insecticidal and Yield Enhancement Qualities of Surround Particle Film Technology in Citrus

      Kerns, David L.; Wright, Glenn C.; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 2002-02)
      Surround WP was evaluated at various spray volumes to determine if volumes lower than the label recommended volume of 250 gallon per acre would provide equivalent citrus thrips control and yield enhancement potential. All the spray volumes evaluated (50, 100, 150, and 250 gpa) appeared to be equally effective. It appears that as long as the spray coverage appears to be visually adequate, then coverage is sufficient. Application of Surround WP led to some increase in fruit size, particularly for the first harvest.
    • Insecticidal Control of Woolly Whiteflies

      Kerns, David L.; Wright, Glenn; Gibson, Rick (College of Agriculture, University of Arizona (Tucson, AZ), 2002-11)
      Four foliar insecticides (Esteem, Provado, Applaud and Assail) and one soil systemic insecticide (Admire) were evaluated for their control of woolly whitefly in lemons. These insecticides were chosen for evaluation because they have demonstrated efficacy to other whitefly species and have little or no impact on whitefly parasitoids. Admire was injected with a single shank about 5-in deep around each tree approximately at the tree’s drip line. All of the foliar insecticides were effective in controlling woolly whitefly. Admire also appeared to have efficacy, but due to inconsistent data on one sample date more testing should be conducted. Six weeks after the beginning of this test, whitefly parasitoids, Eretmocerus comperei or E. dozieri (exact species not certain) reduced the whitefly population across all treatments. Within two more months, no live whiteflies could be found in the test grove, and as of July 15, 2002, there was still no detectable woolly whitefly activity.
    • Insecticide Rotation and Pre-Petal Fall Applications for Citrus Thrips Management

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 2000-10)
      Under low citrus thrips pressure and cool temperatures, Alert, Baythroid, Carzol, Success and Acetamiprid applied at petal fall were all effective control agents. Mid-season applications of Baythroid and Danitol were also effective but appeared to be slightly inferior to Success and Alert in residual control. Despite the prolonged blooming and petal drop period experienced during this trial, plots receiving pre-petal fall applications of Acetamiprid did not produce higher quality fruit than treatments where applications began following petal fall. The fact that thrips densities were low during this period may be the reason. Before pre-petal fall insecticide applications can be deemed useful and economically justifiable, evaluations must be made at higher thrips infestation levels.
    • Insects Affecting Commercial Jojoba Production in Arizona

      Rethwisch, Michael D.; Kilby, Michael W.; Bantlin, Marguerite (College of Agriculture, University of Arizona (Tucson, AZ), 1990-12)
    • Integrated Pest Management of Citrus Mealybug

      Kerns, David L.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 2004)
      Foliar-applied insecticides and the soil-applied insecticide, Admire, were evaluated for their ability to control citrus mealybug on lemons while having a minimal impact on parasitoids. All of the foliar-applied insecticide exhibited activity towards citrus mealybug. The standard insecticide, Lorsban, performed very well, but since this product is especially harmful to parasitoids it is not considered to have a good fit in IPM programs where parasitoid conservation is emphasized. The currently labeled alternative, Applaud, was an effective treatment and should be considered for citrus mealybug control to avoid destruction of parasitoids. Several experimental insecticides showed promise: NNI-850, NNI-750C and NNI-010. However, NNI-0101 at the lower rate of 0.24 lbs-ai/ac appeared to be weak. The addition of narrow range crop oil, NR-415 at 1.0 gal/ac, appeared to be beneficial for initial mealybug knock-down, especially for the slower acting insecticides such as Applaud. Soil injection of Admire at 16 and 32 oz/ac appeared to have very good activity, but due to variability in the mealybug population, more data should be collected to confirm this finding.