Abstract:Cecidomyia weni Jiang was firstly found in a Pinus tabulaeformis Carr. seed orchard in Xingcheng, Liaoning Province in 1987. It is bivoltine. The larvae mainly feed on the first year cones causing serious injury. Male inflorescences also can be damaged. Its larvae drop to the ground and pupate, then overwinter in cocoons in the litter. At least three species of parasitic natural enemy are found, including Capellia coni Yang, pyrethroid and phosphoramidate are effective to control the adult of C.weni Jiang.