Ethyl formate + nitrogen fumigant: a new, safe, and environmentally friendly option for treating a 20 ft shipping container loaded with general freight

Abstract

The use of shipping containers for cargo transportation has the potential to transport insect pests from infested to non-infested areas. Fumigation is required as an appropriate biosecurity measure to exterminate insect pests. Fumigation trials were conducted in a 20 ft general purpose (GP) shipping container. Four species of mixed-age cultures, Lasioderma serricorne (F.), Sitophilus oryzae (L.), Trogoderma variabile (Ballion), and Rhyzopertha dominica (F.) were used for bioassays. Ninety g m−3 of ethyl formate + nitrogen formed non-flammable ethyl formate fumigant formulation was released into the container. The fumigation yielded sufficient concentration × time (Ct) products at a range of 437.54–449.19 g h m−3 in the container for exterminating all life stages. Ethyl formate left no residue in treated drinks. This study demonstrated that on site generation of a non-flammable ethyl formate and nitrogen fumigant can be achieved and this new application technology ensures that ethyl formate distributes evenly in the container within 30 min after application and with a variation of <3%. The research further demonstrated that an ethyl formate + nitrogen application can be used as a pre-shipment treatment for controlling all the stages of insect pests in a shipping container. After a fumigation holding period and ventilation of 15 min, ethyl formate was successfully removed from the container at 0.5–35ppm in different locations. The levels of ethyl formate in the workspace were <0.5 ppm during application, fumigation, and aeriation, which is about 5% of the 100 ppm level for ethyl formate.