The present invention provides: a resin composition which includes a polyethylene resin, and 5-chloro-4-ethyl-6-[2-(4-trifluoromethylphenyl)ethylamino]pyrimidine; an insect pest control material obtained by causing the 5-chloro-4-ethyl-6-[2-(4-trifluoromethylphenyl)ethylamino]pyrimidine to be held on the polyethylene resin; and a pest control method provided with a step in which the insect pest control material is placed in the habitat of a pest.