Host plant acceptance by insect is determined by the response of gustatory organ and olfactory sensilla. Active ingredient of neem extract Azadirachtin is non-volatile; therefore, response of insect gustatory neurons receptors is critical in determining host. On several lepidopteran larvae, azadirachtin stimulate at least one deterrent neuron at maxillary styloconic sensilla that inhibit larvae to feed (Blaney & Simmonds, 1995). Effect of neem seeds extract as anti feedant can be examined from feeding capacity of DBM larvae after treatment. On feeding test, 24 h after treatment the amount of leaf consumed by the larvae fed with leaf treated with neem seeds extract at various concentration was not different from those eaten by larvae fed with clean leaf (control). However, after 48 h onward the feeding capacity of treated larvae was significantly lower than the control larvae. After 72 h, larvae that previously fed with leaf dipped into 0.32% neem seeds extract, significantly consumed less leaf than those fed with leaf treated with 0.04 % or 0.08% or fed with clean leaf (control), but consumed no significantly differ from leaf treated with 0.16% neem seeds extract (Table 3).