N. Senthilkumar, S. Murugesan, K. B. Vijayalakshmi, M. Monisha, D. Suresh Babu, R. Lakshmidevi and P. Manivachakam
Plants and their mobile/immobile chemical constituents play an important role in the development of biopesticides. The present study envisaged to assess the effect of plant extracts against the teak larvae, Hyblaea puera (Lepidoptera:Hyblaeidae) which is considered as major pest that strongly influences the development of teak tree. Eight plant species have been selected based on ethnobotanical records for the study. Different organic solvents such as acetone, methanol and ethyl acetate were used for extraction purposes. Higher extract yield and total phenolic content were obtained using organic solvent methanol as compared to other organic solvents. Individual phenolic profiles were estimated from all extracts in which most of the compounds were found responsible for biopesticidal efficacy. The extractive efficiency of individual phenolic compounds were higher in ethyl acetate and methanol extract when compared with acetone extract. Among the eight plant species employed for bioassay study Melia dubia, Briedelia scandens, Adhatoda vasica, Vitex negundo, Strychnos nuxvomica exhibit 100 percent mortality and other plants showed 80 percent mortality at 1000 ppm concentration. The highest insecticidal activity influenced by the presence of phenolic compounds in plant extracts is also discussed in this article.
