Absence of the quarantine pest Elytroteinus subtruncatus in East Hawaii sweetpotato fields

Abstract

Hawaii is unable to export its unique varieties of sweetpotatoes without quarantine treatment against four high-risk internal pests: West Indian sweetpotato weevil, Euscepes postfasciatus, sweetpotato vine borer, Omphisa anastomosalis, and ginger weevil (or Fijian ginger weevil), Elytroteinus subtruncatus are federal quarantine pests, and sweetpotato weevil, Cylas formicarius elegantulus is a quarantine pest for California and much of the southwestern U.S. In 2003, irradiation treatment at a dose of 400 Gy was approved to provide quarantine security for sweetpotatoes exported from Hawaii to the U.S. mainland (Federal Register 2003, 2004). Whereas sweetpotato is a known host for West Indian sweetpotato weevil, sweetpotato vine borer, and sweetpotato weevil, its host status for ginger weevil was uncertain. Our study suggests that commercial sweetpotato is not a pathway for E. subtruncatus and, therefore, sweetpotatoes could be irradiated at 150 Gy for control of these quarantine pests.