Abstract: It is obvious that bushy lac host plants grow up faster and get into operation early in lac production.These plants bear a lot of flowers and seeds and have a long blooming and fruiting peroid,many inorganic elements being depleted in their growth.Their growth are often weakened.Their life are shortened.Due to these resons,the growth of lac insect is checked,the yield of broodlac is low and the quality is poor.It is reported in this paper that development of flower bud can be restrained and the growth of new buds can be promoted by spraying a mixed solution of 0.3% ethrel and 2% carbamide on the flower buds of the plants,then the host plants become stronger with more lateral branches.Therefore,the yield and the quality of broodlac on the host plants can well be improved and the period standing idle is shortened for them.