Analysis Of S. Litura On Castor Leaves

The antifeedant activity of the extracts choice and no-choice test methods, after 24 and 48 hours in each test, against 7 day old (3rd instar) larvae of S. litura on castor leaves. Stock solutions of the test compounds were prepared in the carrier solvents. Further dilution was done in emulsified water by maintaining emulsifier (Tween – 80) level at 0.5 % to yield various concentrations. Castor leaf discs (4 cm diameter) were punched out from the washed and dried castor leaves. Leaf discs were dipped thoroughly in each of the concentration and air dried. Moist filter paper discs were placed in glass Petri plates (9 cm diameter) on which a single treated leaf disc was kept (for no-choice method). In choice method, in each Petri dish, along with a treated leaf disc, one untreated leaf disc of same size was kept. Single pre-starved (3-4 hours), 7-day old larvae of S. litura was released into each Petri plate. Ten replicates were kept for each concentration. Leaf discs treated with solvent emulsified water served as control. The unfed area in each treatment was
When choice bioassay was carried out, the hexane and methanol extracts from roots of A. paniculata did not show any significant activity at various treatment doses, when observations were taken after 24 hours (table 2). When the observation period was extended to 48 hours, antifeedant activity significantly enhanced to 50.53 % at maximum dose (0.1 %) with hexane extract. Antifeedant activity was significantly superior at the higher doses of 0.03%, 0.05%, 0.07% and 0.1% with methanol extract after 48 hours. Like in no-choice bioassay, in choice bioassay too, there was no significant difference between the activity of hexane and methanol extracts during both the observation