Antifeedant activityAntifeedant bio

Antifeedant activity
Antifeedant bioassay was carried out using leaf disc no choice method.
The crude extracts were dissolved in acetone and fresh castor leaf discs of 4-cm
diameter were punched using cork borer and dipped in 0.5, 1.0, 2.5 and 5.0%
concentrations. The leaf discs treated with acetone were used as negative
control. In each plastic petridish (1.5cm x 9cm) wet filter paper was placed to
avoid early drying of the leaf discs and single third instar larva was introduced
into each petridish. Progressive consumption of leaf area by the larva after 24
hrs was recorded in control and treated discs using the leaf area meter. Leaf
area eaten by the larva in plant extract treatment was corrected from the control.
Five replicates were maintained for each treatment with 10 larvae per replicate
(total, n=50) and the percentage of antifeedant activity was calculated using the
following formula.