New feasible quarantine disinfestation using ethyl formate for termites and ants on imported lumber

Authors: KIM, DONGBIN - Gyeongsang National University; KIM, KYUNG - Gyeongsang National University; PARK, MON-GOO - Animal And Plant Quarantine Agency; ROH, GWANG-HYUN - Orise Fellow; Cha, Dong; LEE, BYUNG-HO - Gyeongsang National University

Submitted to: Journal of Asia Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2021
Publication Date: 9/24/2021
Citation: Kim, D., Kim, K.W., Park, M., Roh, G., Cha, D.H., Lee, B. 2021. New feasible quarantine disinfestation using ethyl formate for termites and ants on imported lumber. Journal of Asia Pacific Entomology. 24(4):969-974. https://doi.org/10.1016/j.aspen.2021.08.015.
DOI: https://doi.org/10.1016/j.aspen.2021.08.015

Interpretive Summary: Red imported fire ant (RIFA) is one of world’s most aggressive and destructive invasive pests with huge economic, environmental, and health impacts.Once established in a new area, it is extremely difficult and costly to eradicate RIFA. South Korea has been repeatedly exposed to RIFA recently. Thus, researchers at the USDA-ARS laboratories in Hawaii and at Gyeongsang National University and Animal and Plant Quarantine Agency in South Korea are developing ethyl formate based fumigation protocols to control RIFA intercepted in imported non-food commodities. The authors show that workers of Japanese termite, an established species in Korea, are more tolerant to ethyl formate treatment than both workers and alates (reproductive form) of RIFA. In scale-up (0.65m3) and commercial-scale confirmatory trials (76.4m3) using two species of imported lumber and workers of Japanese termite as EF resistant surrogate of RIFA, ethyl formate fumigation resulted in complete control of Japanese termite workers, suggesting that ethyl formate may be applicable for the disinfestation of RIFA in imported lumber.

Technical Abstract: Recent increases in the interception of exotic ants and termites on imported non-food commodities, such as stone and lumber, at Korean ports may increase the establishment risk of these species, especially Solenopsis invicta, that can bring a wide range of economic and ecological damage. Currently, a relatively long exposure (24h) of methyl bromide (MB) fumigation is the only disinfestation guideline available for the control of ants and termites on such commodities in Korea. In this study, we evaluated the efficacy of ethyl formate (EF) as a potential MB alternative for the disinfestation of ants and termites, especially S. invicta, in imported lumber. When fumigated with EF at 5°C for 1h, S. invicta workers were more sensitive to EF than Japanese termite (Reticulitermes speratus) workers in terms of lethal concentration x time causing 99% mortality (LCt99%). Based on this, R. speratus was further tested as an EF resistant surrogate of S. invicta. When fumigated with EF for 4h at four different temperatures, LCt99% values for R. speratus workers were 108.00, 63.31, 77.24, and 67.24 g h/m3 at 2, 5, 13, and 23°C, respectively. From scale-up (0.65m3) and commercial scale (76.4m3) trials containing two infestation-prone lumber species, 140 g/m3 EF at >5°C for 4h resulted in complete control of R. speratus workers, suggesting that 140 g/m3 4h-EF-fumigation may be applicable as a potential MB-alternative treatment for disinfestation of invasive termites and ants, especially S. invicta, on imported lumber.