• Comparative Efficacy of Insecticide Combinations Against Whitefly Adults in Melons

      Palumbo, John; Byrne, David N.; University of Arizona, Yuma Arizona (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008-01)
      Several large plot field studies were conducted in the spring of 2006 and 2007 to evaluate and compare the efficacy of several insecticides (used alone and in combinations) for knockdown and residual control of adult whiteflies in cantaloupes. Treatments were initiated when adult whitefly populations exceeded action threshold of 2 adults/ leaf. Evaluations of adult and immature control were made a various intervals following each application. The results of this study demonstrate that the synergized pyrethroid still provides the most significant knockdown activity on whitefly adults among registered alternatives in melons. In most cases, the addition of endosulfan (Thionex) with bifenthrinin provided 7-14 days of adult suppression below the action threshold. Residual control of adults was less effective following a second sequential application. Other alternative tank-mix partners with Capture were less effective, but might be useful to use in rotation with the Capture+Thionex treatments to provide adult knockdown. As we anticipated, adult and immature whitefly control did not differ among the bifenthrin formulations (Capture vs. generics). Finally, because of the risk of whitefly resistance and the heavy reliance on pyrethoids in all vegetable crops grown in the desert, new alternatives for adult whitefly control are needed.
    • Efficacy of RADIANT (Spinetoram) Against Western Flower Thrips in Romaine Lettuce

      Palumbo, John; Richardson, Jesse; Byrne, David N.; University of Arizona, Yuma Arizona; Dow AgroSciences, Hesperia, CA (College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2008-01)
      RADIANT, a new 2nd generation spinosyn insecticide has recently been introduced to the vegetable industry that has shown excellent activity against western flower thrips in lettuce. Several studies were conducted over 2 growing seasons at the Yuma Ag Center to evaluate the efficacy of RADIANT against thrips in romaine lettuce. Three trials were conducted in spring lettuce under moderate and heavy population pressure, and two fall trials were conducted under low to moderate thrips pressure. In each study, RADIANT performed statistically comparable to or better than Success for control of thrips, but at lower use rates. It appears to provide better residual activity against larvae than Success and the standard compounds presently used, but does not appear to provide any additional adult efficacy. RADIANT will be an excellent addition to our IPM programs, however because it has the same mode-of-action as Success, it will not provide an additional rotational partner for our resistance management programs.