• 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.
    • Protective and Yield Enhancement Qualities of Kaolin on Lemons

      Kerns, David L.; Wright, Glenn C.; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 2000-10)
      Kaolin (Surround) was highly effective at preventing citrus thrips populations from reaching damaging levels in Arizona lemons. Applications should be initiated before thrips become numerous. Applying the material before petal fall may offer protection of early set fruit, but may not be necessary if thrips densities are low. However, since kaolin should be applied in advance of thrips populations increase, determining the benefits of pre-petal fall applications of kaolin is difficult. Kaolin applied on a maintenance schedule offers continual suppression of thrips populations, whereas traditional standard insecticides offer temporary population knockdown. Kaolin did not interfere with photosynthesis or stomatal conductance, and may possess yield enhancement qualities.
    • Results of Scion and Rootstock Trials for Citrus in Arizona -- 1999

      Wright, Glenn C.; Peña, Marco A.; Wright, Glenn; Kilby, Mike; Department of Plant Sciences, U. of A., Yuma Mesa Agriculture Center, Yuma, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 2000-10)
      Five rootstocks, 'Carrizo' citrange, Citrus macrophylla, Rough lemon, Swingle citrumelo and Citrus volkameriana were selected for evaluation using 'Limoneira 8A Lisbon' as the scion. 1999-2000 results indicate that trees on C. macrophylla and C. volkameriana are superior to those on other rootstocks in both growth and yield. C. macrophylla is outperforming C. volkameriana. Rough lemon is intermediate, and 'Swingle' and Carrizo’ are performing poorly. In a similar trial, Four 'Lisbon' lemon selections, 'Frost Nucellar', 'Corona Foothills', 'Limoneira 8A' and 'Prior' were selected for evaluation on Citrus volkameriana rootstock. 1998-99 results indicate that the 'Limoneira 8A Lisbon' and 'Corona Foothills Lisbon' are superior in yield and fruit earliness. Results from another lemon cultivar trial suggest that 'Cavers Lisbon', 'Limonero Fino 49' and 'Villafranca' lemons may be good candidates for plantings as well. Results from two other lemon scion trials, a navel orange cultivar trial and a 'Valencia' orange trial, and a mandarin trial are presented as well.
    • Use of a Slow Release Triazone-Based Nitrogen Fertilizer on Lemon Trees

      Wright, Glenn C.; Peña, Marco A.; Wright, Glenn; Kilby, Mike; Department of Plant Sciences, U. of A., Yuma Mesa Agriculture Center, Yuma, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 2000-10)
      Trisert CB replaced conventional foliar applied low-biuret urea and liquid urea ammonium nitrate in a typical N fertilization regime, a urea triazone based N source. There was no yield decrease, change in fruit size or grade with the use of the Trisert CB. There were no differences in leaf P, K, Ca, Mg, Cu, Fe, Mn or Zn concentration. Occasionally, leaf N concentration of trees supplied with foliar applied Trisert CB was higher than that of the control treatment.