Abstract: The Massonis Pino Caterpillar occures two to three generations every year in the pine stands in the mountainous regions of Jiangning and Lishui counties, Jiangsu Provinee, usually two generations. Most larvae overwinter in needle clusters at the tips of trees in younger stands attacked by the pest.The average destruction of pine needles by a single larva is 2834.10cm in length (about l3.40g fresh weight or 5.04g dry weight). There are significant variations of amounts of feeds and excrement between male and female larvae. Instar larvae at their last stage defoliat about of the feeds consumed by the larva 70-80% in its whole larvae period.