Abstract
Two field experiments were undertaken in Puerto Rico, one in Isabela and another in Mayagüez, to determine the susceptibility of several cultivars of Ipomoea batatas (L.) (Lam.) to Cylas formicarius var. elegantulus (Summers). Although the total yield of the cultivars was not affected by the initial injuries caused by the insect, the quality of the tuber was affected in both experiments. The degree of susceptibility in each experiment was determined from the internal damage and the number of larvae in the tubers. In Isabela, cultivars WRAS-3, WRAS-7, WRAS-31, WRAS-36, Mojave and Gem were highly susceptible to the weevil attacks, whereas varieties Regal and Sumor and the WRAS-7 line were moderately susceptible. In Mayagüez cultivars WRAS-36, Mojave, Miguela and Gem were highly susceptible to the attack of the insect. Cultivars WRAS-3, WRAS-7, Resisto, Sumor, WRAS-25, WRAS-31, WRAS-35, were moderately susceptible. Variety Regal and the WRAS-37 and WRAS-40 lines were the most resistant to the attack of Cylas formicarius.