• The Response of Table Grape Growth, Production, and Ripening to Water Stress

      Garrot, D. J.; Gibson, R. D. Jr.; Kilby, M. W.; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      Four year old 'Flame Seedless' grapevines, located in a commercial vineyard, were subjected to increased water stress levels based on infrared canopy temperatures and the Crop Water Stress Index (CWSI) for two years. CWSI levels were approximately .18, .30 and .33 for the wet, medium and dry treatments. In the first year there were no significant differences in yield however, there was a significant reduction in the amount of water applied in both the medium and dry treatments when compared to the wet treatment. In addition, the wet treatment had significantly greater growth during the first growing season when comparing pruning weights.
    • Results of Scion and Rootstock Trials for Citrus in Arizona - 1997

      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)
      Five rootstocks, 'Carrizo' citrange, Citrus macrophylla, Rough lemon, Swingle citrumelo and Citrus volkameriana were selected for evaluation using 'Limoneira 8A Lisbon' as the scion. Early results indicate that trees on C. volkameriana and C. macrophylla are superior to those on other rootstocks in both growth and yield. 'Swingle' and Carrizo' are performing poorly. In a similar trial, Four 'Lisbon' lemon selections, 'Frost Nucellar', 'Corona Foothills', 'Limoneira 8A' and 'Prior' from the University of Arizona Citrus Budwood Certification plot were selected for evaluation on Citrus volkameriana rootstock. Early results indicate that the 'Limoneira 8A Lisbon' selection is outperforming the other selections in both growth and yield. Preliminary results from another lemon cultivar trial and a navel orange cultivar trial are presented as well.
    • Revitalizing "Wichita" Pecan Productivity Through Corrective Pruning - First Year Results

      Gibson, Richard; Kilby, Michael; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      A pruning study was established in stressed pecan trees to identify effective means of returning unproductive trees to full productivity. The study was comprised of two pruning systems and one untreated check. The number of nuts harvested from pruned trees was lower than that harvested from the unpruned trees, but the quality of the nuts from the pruned trees was improved when compared with the unpruned trees.
    • Seasonal Abundance and Field Testing of a Citrus Thrips Temperature Development Model in Arizona Citrus

      Rethwisch, Michael D.; McDaniel, Charles; Peralia, Manuel; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      Citrus thrips populations (adults and nymphs) were monitored through the spring of 1991-1992 in several locations throughout most of the commercial citrus production areas in Yuma County to determine if citrus thrips seasonality was similar to that previously reported in California. Study findings indicate that seasonality is similar throughout the winter and very early spring. Adult thrips numbers increase rapidly in groves due to attractive foliage, whether it is weeds or citrus. High nymph numbers did not always follow adult peaks, and were not statistically correlated. Predatory mites and rains may have affected 1992 results.
    • Susceptibility of Lemons to Citrus Thrips Scarring Based on Fruit Size

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      Lemons appear to be most susceptible to damage by citrus thrips from petal fall until they reach 1.0 inch in diameter. Correlation analysis suggests that fruit greater than 1.0 inch in diameter may not be highly susceptible to thrips scarring and thus may not require protection. 1f this relationship can be verged with additional data, late- season thrips sprays may be avoided.