Effects of the different fertilization，date of transplanting and rice varieties on ocurreace of hydrdtia sasakii

The circumstances of rice injured by hydrellia sasakii under different fertiiizations，date of transplanting and varieties were investigated in 1994～1996 The results show that there are no significant difference in the numher of iniured plants by hydrellia sasakii on thesame variety in various fertilizer treatments，while significant difference exists when theseedling transplanted at different dates．As date of transplanting is put off，the rate of injuredplants increases significantly．81 varieties that have some resistance have been selected.