2013 Annual Report
Conventional fruit fly control methods such as ground treatments rely heavily on organophosphate insecticides. Continued registration of many organophosphate insecticides for use in the U.S. is in doubt. A current example is the loss of diazinon as a ground treatment for fruit flies. In a cooperative research effort Agricultural Research Service (ARS), Animal and Plant Health Inspection Service (APHIS), university, and state scientists have been looking for alternatives. Eight insecticides, including the natural bioinsecticide, spinosad and the semi-synthetic insecticide spinetoram, as well as two synthetic pyrethroids, an insect growth regulator, an anthranilic diamide, and an organophosphate were evaluated in Hawaii as soil drench treatments for control of three economically important tephritid fruit fly species, the Mediterranean fruit fly, melon fly, and oriental fruit fly. Specifically, we evaluated Entrust (Spinosad), Radiant SC (Spinetoram), Force CS (Tefluthrin), Force 3G (Tefluthrin), Warrior II (Lambda-Cyhalothrin), GardStar 40% EC (Permethrin), Cyazypyr (Cyantraniliprole), and Intrepid 2F (Methoxyphenocide) in the laboratory for control of these three species and compared their efficacy to Diazinon AG600 (diazinon), the insecticide presently used as a soil drench by the nursery industry in California through special use permits. Two experiments were conducted. In the first, late third-instars ready to pupate were exposed to insecticide-treated sand. In the second experiment, pupae were placed in insecticide-treated sand. Adult emergence was the endpoint evaluated. All of these insecticides, except Intrepid 2F, significantly reduced adult emergence of all three species after exposure as third instars, compared to the control. All insecticides, except Cyazapyr, significantly reduced adult emergence of all three species after exposure as pupae. Cyazapyr significantly reduced adult emergence in C. capitata and B. dorsalis, but not in B. cucurbitae. Radiant SC was not as effective against the larval stage as Diazinon AG600, Warrior II, Force CS, Entrust or GardStar 40% EC, but still quite effective. Over all, Entrust, a natural product (spinosad), and its synthetic counterpart, Radiant SC, were quite effective at reducing adult emergence from soil and may be good alternatives to the synthetic pyrethroids, Warrior II, Force CS, and GardStar 40% EC.