Methyl bromide (MB) had been routinely used in quarantine and pre-shipment (QPS), despite of strong recommendations to replace technically feasible alternatives of it by International Plant Protection Convention (IPPC) and current hazardous issues in workplace related post-fumigation process of imported perishable commodities. Due to insufficient ventilations post-fumigation on imported fruits such as citrus, fumigators and related workers in cold storage, load/unload and packing room has been exposed to hazardous conditions (5-100 ppm, MB’s TWA_TLV = 1 ppm). It’s time to replace newly developed phytosanitary disinfestation methods such liquid ethyl formate (EF) with N2 application. It could provide for safer workplace involved on and post-fumigation process, cost-effectiveness as well as meet the environmental friendly solution.

Since methyl bromide(MB) has been designated as ozone deplete substance(ODS) by Montreal protocol (1989), many MBalternative fumigants like ethyl formate and phosphine gas were developed and commercialized. Ethyl formate(EF) is an effectiveMB alternative fumigant to control insect pests on imported fresh commodities. It is important to develop a proper evaporationmethod to apply EF on large scale fumigation because EF has a high boiling point(54℃). Recently, concurrent treatment ofethyl formate and nitrogen(EF+N2 treatment) has been newly developed. At preliminary test, EF+N2 treatment showed goodevaporation rate and showed high efficacy on quarantine pests without phytotoxicity on fresh commodities. In this trial, we’veapplied the EF+N2 treatment on imported orange and lemon at pilot scale (0.5m3, 10m3) containers and commercial scale containerto validate efficacy and phytotoxicity. 70g/m3 of EF liquid was applied on orange and lemon by EF+N2 treatment method,and showed 100% mortality on tested insect pest(Tetranychus urticae) without phytotoxicity at 0.5m3 and 10m3 scale fumigationtrials, respectively. At commercial scale trial, EF+N2 treatment also showed 100% efficacy on T. urticae and there was nophytotoxic symptoms on imported orange and lemon fruit. These results indicate that the newly developed EF+N2 treatmenthas a potential as a MB alternative, and can be applied on imported fresh commodities for quarantine and pre-shipment purpose.

Though quarantine use of methyl bromide(MB) is currently permitted in Korea, there has been phasing out and considering ban in many countries due to their ozone depletion properties. VapormateTM, a new gas formulation of ethyl formate(EF) with carbon dioxide, and VivakilTM, a new gas formulation of phosphine(PH3) with carbon dioxide, are MB alternative fumigants to methyl bromide(MB). For applying on import commodities, the efficacy of EF and PH3 was evaluated for 2hr fumigation on egg, nymph and adult stage of citrus mealybug(CMB), Planococcus citri, at two different temperatures(8, 13℃). The CT(Concentration X Time) product of EF to be expect 99% mortality to egg, nymph and adult stage of CMB were 108.3, 22.4 32.4 gh/m3 at 8℃ and 83.2, 25.1, 29.8 gh/m3 at 13℃, respectively. The CT product of PH3 gas to be expect 99% mortality to nymph and adult stage of CMB were 6.50, 2.55 gh/m3 at 8℃ and 3.72, 3.64 gh/m3 at 13℃, respectively. However, PH3 gas applied at high CT(4.2 gh/m3) for 2hr fumigation was not enough to obtain CT to egg stage of CMB at both temperature conditions. These efficacy data based on CT will be useful to predict the CT model in scale-up fumigation at diverse practical conditions.

For replacement of methyl bromide(MB) in Korea, VapormateTM, a gas formulation of ethyl formate(EF) with carbon dioxide, are firslty introduced in import bananas and VivakilTM, a gas formulation of phosphine(PH3) with carbon dioxide, are ready to commercial use in export cut flowers. Their applications are being extended for other import and export commodities. Ethyl formate have been shown to have effectiveness short exposure time(<4hr) but it has a limited application at low temperature for TSM(Two spotted spider mites) due to some phytotoxic to strawberry. Phosphine gas has demonstrated their efficacy to TSM at low temperature but only meets quarantine requirement when applying longer fumigation time(>24hr) to control CA(cotton aphids). We firstly evaluated two MB alternatives, EF and PH3, have enhansive effect within short exposure time(4hr) at low temperature(5℃) for controlling both TSM and CA without any injury to export strawberries.