Abstract: During 1984-1988, releases of T. dendrolimi was made in 70,000 mu (15 mu=1 ha.) of apple orchards in Shandong Province to control apple leafroller, Adoxophyes orana. The average parasitization of the egg masses and eggs of the pest was 92.41% and 87.2%, respectively, and the percent damaged fruits was reduced to 2-3%, a better control effect than by using chemical insecticides. The parasite was released four times a year on 8-12 releasing sites with a total of 120,000 wasps released per mu. Results of the dispersal study with P³² labeled wasps showed that 61.96% of the parasites dispersed within 5 m distance in the first 6 hr. of the release, and dispersed evenly to 30 m by 24 hr.