The efficacy of four granular insecticides, carbofuran, bendiocarb, BPMC, and isoprocarb were assessed for tungro prevention and its control by root zone application method. All these insecticides were proved to be similar in persistency in greenhouse tests up to 37 days after treatment showing both in preventing tungro infection and causing vector mortality. In field tests using two rice cultivars, Taichung (Native) 1 and Ratna, carbofuran as root zone application was found to be much superior to broadcast application. There was no significant difference between 1 and 2 kg a.i./ha. The effects of bendiocarb, BPMC and isoprocarb as root zone application were almost similar to broadcast application of carbofuran.