The West Indian sweet potato weevil, Euscepes postfasciatus (Fairmaire) is a serious pest of sweet potatoes in the Caribbean and Central America, California and Hawaii. Damage is similar to sweet potato weevi, Cylas formicarius. Hot and dry weather favors weevil development. At optimal temberature range of 27-30 Celssius weevil completes it life cycle in 33 days. Detection of early infestation is not easy as adults are most active at night. Early dectection can be accomplished by checking the base of plants for feeding puctures and exit holes.
South America, Greater and Lesser Antilles, California, Hawaii, Tahiti and Old world.
Sweetpotato and wild species in the genus Ipomoea.
Adult weevils feed within vines and storage roots. Larvae cause most damage by tunnelling within the storage roots.
Biological and Ecological Notes
Life history of E. postfaciatus is similar to sweet potato weevil, C. formicarius under field and storage conditions. Adult weevils enter sweet potato fields by crawling or when tubers infested with weevils are dumped near the fields (Yasuda, 1997). Female lays eggs singly in cavaties excavated in vines or in storage roots. Usually, egg cavity is sealed with protective plug. After emegence, larvae tunnel the vines or storage roots and feed inside. Pupation takes place inside the tunnels. A few days later, adult emerge.
Yasuda, K. 1997. Occurence of West Indian Sweet potato weevil, Euscepes postfasciatus (Fairmaire) (Coleoptera: Curculionidae) and damage to sweet potato (Ipomoea batatas (L.) Lam.) fields. Japanese Journal of Applied Entomology and Zoology. 41: 83-88.