Abstract: Experiments on an Integrated Pest Control of the pine bast scale Maisucoccus matsumurae Kuwana have been carried on for ten years since 1973, in a pine stand on the campus of our college. An analysis of the data obtained from the continuous observation on its population fluctuation and its life table showed that the key factor affecting the population dynamics in a newly infested region was the predaceous insects and mites Elatophilus nipponensis, Anystis sp, Oligotrophus sp, etc. They not only fed on the scale, but also transmitted a pathogen, a kind of bacteria, Bacillus thuringiensis var. galleriaestrain matsucoccosae of the pine bast scale. With these enemies, an integrated control of this scale has been successfully established in the pine wood of about ten mu on our campus for ten years. The stand has been growing vigorously and the population of the scale has gone down to a low level.At the same time, surveys were also made in other infested regions in Shandong, Liaoning, Jiangsu, Zhejiang Provinces and Shanghai municipality. It was found out that there always existed a scale source center, characteristics of which were: (1) pines grew too close, moisture high inside the stand; (2) resistance of the tree low, often accompanied with outbreak of secondary pests; (3) lack of effective natural enemies.Another IPC of the scale has been made in a wood of about 100 mu on the phoenix Hill near Hangzhou since 1978. After cutting down and removing the dead trees, natural enemies from our campus and Liaoning Province were introduced to the Phoenix Hill. Two years later, after about 4 generations, the population of the scale went down to about 5% of the original number, which was below the Economic Level (0.56 insect/10cm2) and the trees returned to normal growth.According to our experiments, populations of the scale will decrease rapidly if the pathogen is sprayed to the trees in the presence of some predaceous insects and mites.