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.

摘要

甘薯的高生产力潜力受到无数害虫的限制，从而降低了其产量的数量和质量。本研究调查了红薯的害虫，并评估了四种植物提取物（即：番木瓜、印楝、Chromolaena odorata和辣木）对作物害虫的防治作用。实验使用了两个红薯品种（Shaba 和 SPK004）的藤蔓。植物水提取物制备为 10% w/v，并从 4 开始使用 种植后几周（WAP），随后每周一次，直到 10 WAP。甘薯作物在两个种植季节均受到五种害虫的侵扰。种植初期，香芋、番木瓜、油橄榄、印度木瓜植物提取物处理的沙巴品种红薯地块虫害数分别为0.7、0.25、1.67和0.7。并且它们显着 ( p < .05) 低于未处理地块中的害虫数量 (3.08)。其他植物药对种植季早期和晚期害虫数量的影响也得到了类似的结果。经甘薯提取物处理的地块甘薯产量最高（16.14公斤）   C.番木瓜，其产量显着高于 未处理地块的产量（2.60 千克）。用其他提取物处理的其他地块的产量也显着高于未用植物药处理的地块的产量( p  < .05)。 研究得出的结论是，植物提取物可以应用于甘薯，以减少虫害并提高贮藏根的产量。