Abstract BACKGROUND The flighted spongy moth complex (FSMC) lays egg masses not only on host plants but also various artificial structures, such as, cargo, vehicles, and ships. Thus, preventing the transmission of these egg masses is an international challenge. Their eggs are covered with thick hair covering that act as a barrier to insecticides thus making them ineffective. A volatile gas may be able to carry toxic substances past this barrier to the eggs. In this study, we evaluated the insecticidal effect of the highly volatile allyl isothiocyanate (AITC) on Lymantria dispar egg masses and compared it with that of two conventional insecticides containing permethrin, fenpropathrin, and clothianidin. RESULTS In the two conventional insecticide treatments, approximately 50% of the eggs survived when the hairy covering was not removed. In contrast, all eggs, with or without hairy covering, did not hatch after AITC treatment. The LC 50 and LC 90 values of AITC against them were 37.3 ± 5.4 and 100.9 ± 11.8 ppm, respectively. Our results show that AITC at 35000 ppm can eradicate FSMC egg masses. CONCLUSION AITC has a lethal effect against FSMC egg masses and may be applied for the extirpation of eggs/egg masses of various other organisms, besides FSMC. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.