Approved irradiation quarantine treatment doses for Bactrocera cucurbitae, Ceratitis capitata, and Bactrocera dorsalis infesting fruits and vegetables for export from Hawaii to the continental U.S. are 210, 225, and 250 Gy, respectively. Irradiation studies were initiated to determine whether these doses are unnecessarily high and could be reduced. Comparative dose response tests were conducted with wild and lab strains of the three species, both in diet and in fruit. After irradiation treatment, development of each individual in a test was followed until death while recording adult emergence and adult female fertility. B. curcurbitae was the most tolerant of the three species to irradiation. Laboratory and wild strains of B. curcurbitae were equally tolerant of irradiation, and flies were more tolerant when irradiated in fruit compared with diet. An irradiation dose of 150 Gy applied to 50,000 B. curcurbitae mature third instars in papayas resulted in 0 survivors to the adult stage. Lowering the irradiation dose for these quarantine insects would reduce costs and increase capacity for treatment facilities, and minimize quality problems in radiation-sensitive fruits and vegetables. Results support a generic dose of 150 Gy for tephritid fruit flies.
Species 1: Diptera Tephritidae Ceratitis capitata (Mediterranean fruit fly)
Species 2: Diptera Tephritidae Bactrocera cucurbitae (melon fly)
Species 3: Diptera Tephritidae Bactrocera dorsalis (oriental fruit fly)
Keywords: irradiation, quarantine treatment
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