Ashamo  M. O. , Ogungbite  O. C. , Adetogo  T. A.

Federal University of Technology, Biology Department P.M.B 704, Akure, Nigeria
Author    Correspondence author
International Journal of Horticulture, 2018, Vol. 8, No. 9   doi: 10.5376/ijh.2018.08.0009
Received: 30 Jan., 2018    Accepted: 12 Feb., 2018    Published: 13 Apr., 2018

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Ashamo M.O., Ogungbite O.C., and Adetogo T.A., 2018, Insecticidal potency of Newbouldia laevis oil extracts against Sitrotoga cerealella, an important pest of paddy rice, International Journal of Horticulture, 8(9): 98-105 (doi: 10.5376/ijh.2018.08.0009)

The study was conducted to evaluate the insecticidal potency of Newbouldia laevis extracts against Sitrotoga cerealella in the laboratory at temperature of 28±2°C and relative humidity of 75±5%. Oil from the leaf, stem bark and root bark of N. laevis was extracted using methanol as solvent and 1, 2, 3, 4 and 5% concentration of each oil extract were prepared. Results obtained revealed that oil extracted from all the parts of the plant had significant effect on the mortality of the moth but the root bark oil extract appeared to be most effective since it was the only one to achieve 100% insect mortality within 72 h of application at 4% concentration and it requires low concentration1.59 (LC₅₀) to achieve 50% mortality. The extracts reduced the adult emergence of the insect and their ability to cause seed weight loss. Both leaf and root extracts at 4 and 5% concentration prevented adult emergence while seed weight was prevented by all the three plant parts at 4 and 5% concentration. Water absorption capacity as well as viability of the protected paddy was not affected by the oil extracts. Nonetheless, there were significant differences between treatments and the controls in all the parameters tested except for water absorption capacity and viability test. The result obtained presented root extract of N. laevis to be more effective than other plant parts and therefore could be introduce as a counter measure for the control of S. cerealella in storage.

Sitrotoga cerealella ; Newbouldia laevis ; Lethal concentration; Adult emergence; Seed weight loss