Effect of time and proportion of leaf harvest on pest, forage and root yields of sweetpotato (Ipomoea batatas L.) in the inland valley swamp and upland ecologies of Njala

Abstract— Dearth of knowledge exists regarding the leaf harvest intensity and frequency thresholds that support optimum forage and fresh storage root yields in Sierra Leone. A study was carried out to assess the effects of leaf harvesting time and proportion on Cylas puncticollis infestation, growth and yield of sweet potato in the inland valley swamp and upland ecologies of Njala. Treatment combinations comprised of two varieties (“Kabia” and “Gbanie”), four leaf harvest regimes: 0, 30 60 and 90 days after planting (DAP); and four-leaf harvest intensities (0, 25, 50 and 100%). The experiment was laid out in a randomized complete block design (RCBD) with three replications. Data collected included Cylas puncticollis severity on vines and storage roots, root dimensions and numbers, fresh foliage and storage root yields. The results revealed that leaf harvesting twice at 25 and 50% contributed more to optimum forage and storage root yields and related attributes of sweet potatoes compared to other treatments. The present study suggests that good agronomic management of sweet potato that supports optimum forage and storage root yields should be selected to meet the dual purpose for which it is grown. These findings serve as good guide for incorporation of leaf harvesting time, proportion of leaf harvest in germplasm assessment and new population development objectives.