In 2000,field experiment was conducted on performance of 45%disultap SP for control of the rice stem borer,Chilo suppressalis(Walker)in Lujiang County,Anhui Province where the pest was severe.The result showed that the larval mortality were 89.5%,95.0% and 95.9%in treatments sprayed with 472.5g,607.5g and 742.5g(a.i./hm²),respectively,and 87.6%,92.3% and 93.1%in treatments dusted with the same dosages,respectively.The changes in num-bers of damaged plants were roughly the same as the larval mortality.The dusting application method was easy and less harmful to natural enemies,so it was effective and cost saving.Consid-ering material cost,the authors suggest to use the dosage of 607.5g for the present.