ISSN 4391-3199
African Journal of Chemistry Vol. 1 (2), pp. 059-062, November, 2013. © International Scholars Journals
Full Length Research Paper
Ethanolic extract of melgota (Macaranga postulata) for repellency, insecticidal activity against rice weevil (Sitophilus oryzae)
Syed Shayfur Rahman1, Md. Mizanur Rahman1*, Mohammad Mizanur Rahman Khan1, Shameem Ara Begum1, Balaram Roy2 and S. M. Fakruddin Shahed1
1Department of Chemistry, Shahjalal University of Science and Technology, Sylhet, Bangladesh.
2Department of Agricultural Chemistry & Biochemistry, H. M. D. Science & Technology University, Dinazpur, Bangladesh.
*Corresponding author. E-mail: [email protected]. Tel: 880-821-713491(ext. 151).
Accepted 27 August, 2013
Abstract
Ethanolic extract of Melgota is used for repellency, insecticidal activity against rice weevil (Sitophilus oryzae) with emphasis on chemical investigation. Fruits of Melgota (Macaranga postulata) were extracted on different solvents as in ethanol, acetone, petroleum ether, distilled water and the extracts were concentrated and dried. The ethanol extracts of Melgota (M. postulata) of different concentrations were investigated for their repellency and insecticidal activity against S. oryzae. Average mortality percentage indicated that the extracts caused significant mortality and repellency on the target insects and bioassays indicated that the toxic and repellent effect was proportional to the concentration and higher concentration has stronger effect. Observed mortality percentage increased with increase in time intervals after treatment. Mortality percentage at 0.25, 0.50, 0.75, 1.00, and 1.50 h after treatment (HAT) indicated that 4% solution showed the highest mortality (34.0%) in S. oryzae at 1.50 HAT compared to pediculus humanus. Mortality percentage showed parallel response to the level of concentration at different time intervals after treatment. 1% fruit extract of Melgota (M. postulata) showed the lowest repellency 9.84 % in case of rice weevil. On other side, 2% showed 12.76% and 4% showed 22.43% respectively. TLC of crude ethanol extract of Melgota (M. postulata) showed six distinct compounds at uv-visible light.
Key words: Macaranga postulata, Sitophilus oryzae, mortality, repellency.