Treating rice seedlings with chemicals shortly before or after infestation controlled stem borer activity in the stems. The liquid formations were more effective for near immediate protection. There was a lag in the effectivity of the granular formulations shortly after application. The trial showed that two (Triazophos and Mocap applied at 0.75 and 1.00 kg a.i./ha, respectively) of the chemicals tested were effective after 7 days.