Pyrethroid is an ideal insecticide in the IPM. The dosage of decamethrim for the larvae of Dendrolimus punctatus at 3 to 4 stadium is 0.0125g a. i. /mu, for those at 4 to 5 stadium 0.025 a.i./mu, and for those at 5 to 6 stadium 0.05g a.i./mu. The dosage of fenvalerate for the larvae at 3 to 4 stadium is 0.2g a.i./mu, and for those at 5 to 6 stadium 0.4g a.i./mu. These dosages do little damage to natural enemies, and have no toxicity to fishes in the pond, thus producing good results. Overwintering of application are as follows: Dilute the pesticide directly with water to spray by means of LV and ULV, or make it an emulsion and then spray it. Overwintering is the best time for controlling Dendrolimus punctatus because not only the damage to natural enemies can be reduced, but also the effect of pyrethroid can be increased under a lower temperature. The use of ultralight airplanes for this purpose has the following advantages: flexibility, easy operation and low cost.