Concentrations of 10, 1,0.1,0.05 and 0.01 pg/ml of fenoxycarb, and 10, 5 and 1 pg/ml of other 1GR products were applied topically to eggs of Nc.zaru i%+hda. The effects of the treatment and concentration on egg hatching were studied comparatively for each product. Whereas at 10 pg/ml all compounds almost presented 100% of mortality, at lower concentrations most of them lost their activity. Fenoxycarb among all the IGR tested was the most active compound producing 8 1 Yo mortality of 0.1 pg/ml concentration.