Samples of wheat and shelled corn treated with permethrin at 5,10, and 20 ppm and with malathion at 10 ppm were subjected to infestation by adults of the rice weevil at intervals during a 12- month period. Both malathion and permethrin were more effective protectants for corn than for wheat. However, the permethrin treatments of 10 ppm on wheat and of 5 ppm on corn were much more effective protectants than the malathion standard. Residues of malathion degraded rapidly to ca. 2 ppm on wheat and ca. 3 ppm on corn during the first 6 months of the test. There was little or no degradation of residues of permethrin during the 12 month test period.