Disclosed is an arthropod pest control composition comprising 2-(2,6-difluorophenyl)-4-[4-(1,1-dimethylethyl)-2-ethoxyphenyl]-4,5-dihydrooxazole and an inert carrier, wherein the volume median diameter of 2-(2,6-difluorophenyl)-4-[4-(1,1-dimethylethyl)-2-ethoxyphenyl]-4,5-dihydrooxazole is from 1.5 to 5.92-(2,6-디플루오로페닐)-4-[4-(1,1-디메틸에틸)-2-에톡시페닐]-4,5-디히드로옥사졸 및 불활성 담체를 포함하는 절지동물 해충 방제 조성물로서, 2-(2,6-디플루오로페닐)-4-[4-(1,1-디메틸에틸)-2-에톡시페닐]-4,5-디히드로옥사졸의 부피 중간 직경이 1.5 내지 5.9 μm 인 것이 개시된다.
