Distribution of the sweet potato weevil, Cylas formicarius FABRICIUS and the small sweet potato weevil, Euscepes postfasciatus FAIRMAIRE in the Amami Islands

Abstract

The infestation of sweet potato with the sweet potato weevil, Cylas formicarius FASRICIUS and small sweet potato weevil, Euscepes postfasciatus FAIRMAIRE was investigated at 85 sites in the Amami Islands in late autumn of 1985 and 1986. The average rates of damage of the stems and tuberous roots of sweet potato amounted to 49.2% and 15.2%, respectively. E. postfasciatus was distributed in the town of Wadomari in Okierabu Island, Tokunoshima Island, and Amamiooshima Island. Both weevils were distributed in the town of Wadomari town of the Okierabu Island. In Yoron Island, the presence of species of these weevils has not been confirmed.