The present experiments were carried out to reduce the population density of adult pine gall midge, Thecodiplosis japonensi,s UCHIDA et INOUYE, by means of spray the sticky agent C-4, on the ground, herbacious plantation and foliar leaf of pine trees at Sanbonli,. Anyang, Kyungido. And also the 3 periods of treatment, such as before 2 weeks( I ), before 1 week (II) from the peak emergence period and peak emergence period (III) were applied. The experimental results obtained were as follows. (1) The formula of selected sticky agent C-4 was $70\%$ of castor oil, $25\%$ of damar resin and $5\%$ of carnauba wax, and it showed the best both on stickiness and duration, and lower phytotoxicity to the host plant. (2) The reduction of population densities of the adult PGM were $68\%$ and 78f: in the G-I and G-II treatment plot respectively, which compared to control, on the ground spray. (3) And the reduction of population densities were $63\%$ and about $90\%$ in the P-I and P-II plot respectively when the agent was sprayed on the herbacious plantation. (4) The rates of gall formation were $32.8\%,;40.8\%;and;59.4\%$ in the spray plots of F-I, F-II, and F-III respectively, and there was no significant difference among the upper, middle and lower parts of the treated host plant in the rates of gall formation. (5) The effective stage of sticky agent application were considered as before one week from the peak emergence period in tile all types of treatment.