Impact of Oviposition Deterrent Effect of Catharanthus Roseus and Ocimum Sanctum on Adult Females of Spodoptera Litura

Abstract

Oviposition deterrent effect of Catharanthus roseus and Ocimum sanctum was evaluated in choice and no-choice situations on adult females of Spodoptera litura. In choice condition adult females were given choice to lay eggs on treated and untreated oviposition substrate and total eggs laid in first two egg masses were counted. In no-choice condition only treated substrate was provided for egg laying to ovipositing females of Spodoptera litura. Results indicate that leaf extracts of the plants show varying degree of oviposition deterrent activity. In the choice situation, Spodoptera litura females preferred to lay a greater number of eggs on the untreated oviposition substrate compared with the treated substrate with different concentrations of extracts of the plants. As the concentration of the extract increased, egg laying was proportionately reduced. A significant observation was that a gradual decline in oviposition was reported even on the untreated substrate in choice situations. This could be attributed to deterrent effect of volatiles emanating from the treated substrate.