Comparative Efficacy of Insecticide Combinations Against Whitefly Adults in Melons

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.