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Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings Publication Acceptance Date: 11/3/2003 Publication Date: 11/3/2003 Citation: Follett, P.A. 2003. Irradiation as a methyl bromide alternative for sweet potato exports from Hawaii. International Conference on Methyl Bromide Alternatives and Emissions Reductions 2003. Interpretive Summary: Hawaii's sweet potato [Ipomoea batatas (L.) Lam.] growers produce several unique varieties of sweet potatoes-including a purple-fleshed type (also called "Okinawan")-that are in high demand. Sweet potato growers in Hawaii are unable to ship sweet potatoes to the U.S. mainland without a quarantine treatment because of the presence of two regulatory pests: West Indian sweet potato weevil, Euscepes postfasciatus (Coleoptera: Curculionidae), and sweet potato vine borer, Omphisa anastomosalis (Lepidoptera: Pyralidae). Preliminary results with the adult stage of the two pests suggest 250-300 Gy may be sufficient to prevent reproduction and a suitable dose to ensure quarantine security in exported sweet potatoes. Based in part on results from the early stages of this research, USDA-APHIS published an interim rule (Federal Register, June 26, 2003) allowing interstate movement of sweet potatoes from Hawaii with an irradiation treatment of 400 Gy. Since the rule was published, 40,000-50,000 lbs of sweet potatoes per week have been exported from Hawaii to the U.S. mainland with irradiation treatment. Technical Abstract: Hawaii's sweet potato [Ipomoea batatas (L.) Lam.] growers produce several unique varieties of sweet potatoes-including a purple-fleshed type (also called "Okinawan")-that are in high demand. Sweet potato growers in Hawaii are unable to ship sweet potatoes to the U.S. mainland without a quarantine treatment because of the presence of two regulatory pests: West Indian sweet potato weevil, Euscepes postfasciatus (Coleoptera: Curculionidae), and sweet potato vine borer, Omphisa anastomosalis (Lepidoptera: Pyralidae). Studies demonstrated that the adult stage is the most tolerant of irradiation in both species. Irradiation of 31,000 West Indian sweet potato weevils at a dose of 150 Gy resulted in no reproduction. Irradiation of 900 sweet potato vine borers at 250 Gy resulted in no reproduction. Sweet potato quality research indicates that roots irradiated at 600 Gy suffer no loss in quality (M. Wall, USDA-ARS, Hilo, Hawaii); higher doses have not been tested. Based in part on results from the early stages of this research, USDA-APHIS published an interim rule (Federal Register, June 26, 2003) allowing interstate movement of sweet potatoes from Hawaii with an irradiation treatment of 400 Gy. Since the rule was published, 40,000-50,000 lbs of sweet potatoes per week have been exported from Hawaii to the U.S. mainland with irradiation treatment. |
