Comparative investigation on oviposition deterrence of essential oils from and Vitex pseudo-negundo on Callosobruchus maculatus (Haussk) Hand. I. MZT. on laboratory

Recently, there has been a growing interest in research concerning the possible use of plant extracts as alternatives to synthetic insecticides. Essential oils are among the best-known substances tested against insects. These compounds may act as fumigants, contact insecticides, repellents, antifeedants and may affect growth and development of the insect. The objective of the present study was to test the possible properties of, medicinal plants, Carum copticum C. B. Clarke (Apiaceae) and Vitex pseudo-negundo (Haussk) Hand. I. MZT. (Verbenaceae) essential oil vapors against Callosobruchus maculatus (F.) to elucidate their deterrency on oviposition. The experiment was conducted with six concentrations (0.02-0.5 ml oil per one gram seed) at 27 ± 1°C, 60 ± 5 % R.H. and in dark condition. The essential oils were obtained from dry seeds of C. copticum and leaves of V. pseudo-negundo subjected to hydrodistillation using a modified clevenger-type apparatus. In each vial, two pairs of adult insects and 10 g chikling vetch were used. Oviposition deterrence of C. copticum was significantly higher than V. pseudo-negundo. At the highest concentration (0.5 ml per one gram seed) oviposition deterrence was reached to 100% and 76.33% by C. copticum and V. pseudo-negundo, respectively. Our results showed that these essential oils exhibited strong oviposition deterreny on C. maculatus at sublethal doses.