Field Evaluation of Plant Extracts in the Management of Megalurothrips sjostedti and Maruca vitrata of Cowpea in Southeastern Nigeria

ABSTRACT: The study evaluated the impact of plant extracts (Azerachita indica, Allium sativum and Zingiber officinale) in the management of post-flowering insect pests (Maruca vitrata and Megalurothrips sjostedti) of cowpea against synthetic insecticides, during 2011/12 farming seasons in Nigeria. The results indicated that the incidences of Maruca vitrata and Megalurothrips sjostedti were significantly influenced by the application of Azerachita indica, Allium sativum and Zingiber officinale aqueous extracts in a descending order respectively. At the application of Azerachita indica and Allium sativum extracts at 10% concentration, they significantly (P < 0.015) reduced the abundance of Megalurothrips sjostedti and Maruca vitrata, decreased the cowpea pod damage comparatively to Uppercott at 1.5 kg a.i. ha-1 standard check. Results of the experiments showed that all the plant extract treatments were significantly better than control treatment. Similarly, yield results corresponded positively with the effectiveness of the treatments. Grain yields were significantly higher in plots treated with Azerachita indica, Allium sativum extracts compared to plots treated with Zingiber officinale and the control. Results of the present finding therefore suggest the use of all the tested plant extracts in the management of cowpea pests and could serve as an alternative to synthetic insecticides. It is cheap, safe, and environmentally friendly and if adopted could increase cowpea production in Nigeria especially for the resource poor farmers.