Forty sweet potato cultivars Ipomoea batatas (L.) Lamarck were studied in relation to their resistance to Euscepes postfasciatus Fairmaire. Firstly the attractivity and non-preference for feeding and oviposition on stems and roots were evaluated. From the results, eight resistant and two susceptible cultivars were selected. Secondly roots from selected cultivars were used to study the sweet potato resistance to E. postfasciatus. Sweet potato stems and roots were offered to adults of E. postfasciatus in arenas with free choice tests with six replications. Evaluations were carried out after 5, 10, 30, 60 min, 3h and 24h. The better length of stems, among those tested was 35 cm. Sweet potato weevil adults when released in arenas, quickly attached the more attractive plants, preferring the thick stems or leaves insertion. The cultivars with less attractive stems were: Rocha da Paz, Mineira, Lagartixa and Bom Nome. Roots from Lagartixa and Bom Nome cultivars were less damaged. These cultivars and Caboatã were not preferred to oviposition. Roots and stems from Granfina and UFRPE cultivars were more attractive and more damaged. These cultivars must be avoided while Lagartixa and Bom Nome are recommended to be cultivated in areas with the sweet potato weevil.
Insecta; Ipomoea batatas; west Indian sweet potato weevil
