Sorption analysis of ethyl formate fumigation for the management of hitchhiking insect pests in miscellaneous goods

This study analyses the sorption of ethyl formate on miscellaneous goods to develop a phytosanitary treatment guideline for hitchhiking pests. Moreover, it evaluates whether the concentration of ethyl formate reaches a level that disinfects the target pests. The rising volumes of miscellaneous imported goods, such as sorghum brooms, ground plant materials (such as cocopeat), and processed plant products (including chairs and decorative items), have increased the risk of pest introduction. Laboratory-scale experiments have shown that the sorption rates of EF vary among different product categories, with ground plant materials showing the highest sorption: 65 % on sorghum brooms and 78 % on ground plant materials (P < 0.05). Scale-up fumigation has also shown similar patterns of sorption on different product categories: 76 % on sorghum brooms and 80 % on ground plant materials (P < 0.05). Commercial trials confirmed that EF sorption was higher on ground plant material than on sorghum brooms under actual conditions in imported containers. Although the remaining concentrations on the items differed based on variations in sorption, the concentration-time (Ct) products for all tested items exceeded the LCt_{99 %} values (Ct value for disinfecting 99 % of pests) for multiple pest species. Moreover, EF showed a uniform distribution and effective pest control capabilities at a concentration of 70 g/m³ for 4 h at > 15 °C, which reflects the standard treatment period commonly applied for EF fumigation during Korean quarantine processes. These results suggest that EF fumigation is a viable alternative to methyl bromide, thereby offering both environmental benefits and improved worker safety.