Ethyl formate-based quarantine treatment for exotic ants and termites in imported rubber plants and stone products

Authors: KIM, DONGBIN - Kyungpook National University; KWON, TAE HYUNG - Kyungpook National University; PARK, MIN-GOO - Jeonbuk National University; KIM, KYUNG WON - Animal And Plant Health Inspection Service (APHIS); Cha, Dong; LEE, BYUNG-HO - Kyungpook National University

Submitted to: Applied Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2022
Publication Date: 6/15/2022
Citation: Kim, D., Kwon, T., Park, M., Kim, K., Cha, D.H., Lee, B. 2022. Ethyl formate-based quarantine treatment for exotic ants and termites in imported rubber plants and stone products. Applied Sciences. 12(12). Article 6066. https://doi.org/10.3390/app12126066.
DOI: https://doi.org/10.3390/app12126066

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 HI and at Kyungbook 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 using workers of Japanese termite as EF resistance surrogate of RIFA. In commercial-scale confirmatory trials using two species of imported rubber plants and pieces of marble, ethyl formate fumigation resulted in complete control of Japanese termite workers, suggesting that ethyl formate may be applicable for the disinfestation of RIFA hitch-hiking imported rubber plants and marble products.

Technical Abstract: Exotic ants and termites, including Solenopsis invicta, are frequent hitchhikers intercepted from miscellaneous non-food commodities. In particular, S. invicta has been intercepted in Korea in imported nursery plants, stone, and lumber products, which increases the potential for establishment of this destructive invasive pest in Korea. In this study, we conducted commercial-scale fumigation trials to evaluate ethyl formate (EF) as a potential alternative of methyl bromide using two species of imported rubber plants and pieces of marble as representative good and workers of Reticulitermes speratus as an EF-resistant surrogate for S. invicta. EF treatment at 35 g/m3 for 4 h at >15', the dose required for LCt99% (lethal Concentration x time product required for 99% mortality of R. speratus), resulted in complete control of R. speratus workers tested with rubber plants (Ficus benghalensis and F. retusa) and marble, 9% (w/v) and 60% (v/v) loading ratios, respectively. EF treatment did not adversely affect leaf chlorophyll content, leaf color, and overall health of rubber plants nor affect the visual appearance of the marble. Our results suggest that EF fumigation is a potential alternative to MB for disinfestation of hitchhiking invasive termites and ants, including S. invicta, on imported rubber plants and stone products.