Daealus tuberosus Minimize
August 2003. A request from the Northern Marianas Islands for the identification of a weevil in sweet potato. The weevil is more than twice the size of West Indian sweet potato weevil Euscepes postfaciatus (F.) and the Sweet potato weevil, Cylas formicarius (F.). It causes internal tunneling in the stems or tubers and scoring of the tuber skin by the grubs. The head is elongated into a snout which curves downward with two psuedo-antennnae close to the tip that resembles Cylas sp. The weevil pupates in the stem or root, making tunnels to do so.

Those in the photos emerged after one month from unwashed sweet potatoes.

It was thought to be the Ginger weevil, Elytroteinus subtruncatus, which does not only attack ginger. However, it was later identified as Daealus tuberosus, a Cryptorhynchine weevil, the larvae of which generally live on decomposing vegetation. This beetle was originally described from Guam, so Rota appears to be a new locality. There are records of specimens being collected on Piper, Pipturus and Hernandia by Otto Swezey - these were probably collected by beating these plants, as there is no mention of rearing them.