Assessment of insect pests of sweet potato (Ipomoea batatas L.) and control with botanicals

Abstract

The high productivity potential of sweet potato is restricted by myriads of insect pests that reduce the quantity and quality of its yield. This study investigated the insect pests of Ipomoea batatas and evaluated extracts from four botanicals namely: Carica papaya, Azadirachta indica, Chromolaena odorata and Moringa oleifera for the control of insect pests of the crop. The vines of two varieties of I. batatas (Shaba and SPK004) were used for the experiment. Aqueous extracts of the botanicals were prepared at 10% w/v and applied as from 4 weeks after planting (WAP) and subsequently at weekly intervals till 10 WAP. Five insect pests infested sweet potato crop in both planting seasons. In the early planting season, the number of insect pests in the plots of Shaba variety of I. batatas treated with plant extracts of C. odorata, C. papaya, M. oleifera and A. indica was 0.7, 0.25, 1.67 and 0.7 respectively and they were significantly (p < .05) lower than the number of insect pests (3.08) in untreated plots. Similarly result was obtained for the effects of other botanicals on the number of insect pests in both early and late planting seasons. The yield of sweet potato (16.14 kg) was highest in the plots of sweet potato treated with extract of C. papaya and it was significantly higher than the yield (2.60 kg) from the untreated plots. The yield from other plots treated with the other extracts were also significantly (p < .05) higher than the yield from the plots not treated with botanicals. The study concluded that the plant extracts can be applied on sweet potato to reduce insect infestation and enhance yield of storage roots.