Residual Toxicity of Certain Grain Protectants to the Rice Weevil and Red Flour Beetle on Wheat

Relative efficacy of four insecticides was evaluated as grain protectants on rice and wheat. Deltamet hrin at 2 ppm afforded good protection, followed by fenitrothion at 20 ppm for six months. Fenvalerate and cypermethrin (2 and 5 ppm) and deltamethrin (1 ppm) caused similar mortality throughout the experimental period.