Coconut scale, Aspidiotus destructor Signoret (Homoptera: Diaspididae), is a quarantine pest of banana (Musa spp.) and many tropical crops. Irradiation was examined as a potential phytosanitary treatment to control coconut scale. Dose–response tests were conducted with second-stage nymphs, adult females without eggs, and adult females with eggs at a series of irradiation doses between 60 and 200 Gy to determine the most tolerant stage. The adult female with eggs was the most tolerant stage. In large-scale validation tests and dose–response tests, a total of 32,716 adult female scales with eggs irradiated with doses between 100 and 150 Gy produced no F₁ adults with eggs. Irradiation treatment with a minimum absorbed dose of 150 Gy should provide quarantine security for coconut scale on exported commodities.