STUDIES ON ANTIFEEDING MECHANISM AND ELECTROPHYSIOLOGICAL METHOD AS A BIOASSAY MODEL WITH LARVAL OF OSTRINIA FURNACALIS GUENEE

Toosendanin, Plumbagin and 25 Clerodanes were first tested for their antifeeding activities against the fifth instar larvae of Ostrinia furnacalis.Sensory disrupting experiments pointed the maxillary styloconic sensilla to be the target sites of antifeedants. Further electrophysiological studies with tip-recording mode showed that antifeedants could both reduce impulse frequency of lateral styloconic sensillae evoked by sugar and produce particular impulses at medial styloconic sensillae. Moreover, taking all the chemicals into account, impulse frequencies at medial styloconic sensillae and antifeeding rates in behavior test exhibited prominent positive correlation suggesting that sensory activity explained well for the behavior response and electrophysiological method might be applied in detection of antifeedants as a screening model to quickly assess the potential behavioural effect of a compound using minute amounts of test material.