Toxicity of Malathion to Gamma-Irradiated and Nonirradiated Adult Red Flour Beetles134

Tests were conducted to determine the effect of combining treatments of malathion and gamma radiation applied to adult Tribolium castaneum (Herbst). Radiation was applied before the chemical treatment. The dosage of 5 krad did not produce any mortality when applied alone and actually afforded some protection to the insects against the malathion. At dosages of 10 krad or more, however, radiation combined with malathion at the rate 0.05 μg/insect was slightly more lethal than either malathion or radiation alone. Combination treatments produced earlier mortalities than did radiation alone.