Abstract
BACKGROUND: The brown marmorated stink bug (Halyomorpha halys) (BSMB) is a biosecurity threat globally. Its most likely avenue of entry is via shipping transport of a multitude of commodities. Currently employed biosecurity treatments (methyl bromide, sulfuryl fluoride) pose several concerns including climate change, environmental and occupational health and safety. Ethyl formate with dilution in carbon dioxide has been shown to be an effective biosecurity treatment for controlling BMSB. Carbon dioxide is a known synergist in fumigation and is a greenhouse gas contributing to climate change. RESULTS: Laboratory and commercial-scale bioassays were conducted to evaluate the efficacy of ethyl formate in controlling diapausing and non-diapausing BMSB. In both trials and all treatment conditions, ethyl formate concentrations >12 mg L(-1) without dilution in carbon dioxide for 3-h exposure periods were effective in achieving insect control. These results were consistent with existing literature and showed the rapid action of the fumigant in achieving a desirable level of insect mortality. The results demonstrate that even without the synergist carbon dioxide, ethyl formate can achieve complete mortality of both non-diapausing and diapausing BSMBs at a dose rate lower than the currently registered 90 mg L(-1). CONCLUSION: The results of this research show the commercial viability of ethyl formate, without dilution with carbon dioxide, as a biosecurity treatment for the control of BMSB, both non-diapausing and diapausing. These results will also assist in progressing the registration of the fumigant with relevant National Plant Protection Organisations. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.