The current protocols of methyl bromide (MeBr) fumigation on imported nursery plants, which are seriously infested with quarantine mealy bugs and scales, could be reevaluated because there were no limited uses of loading ratio, packing types etc. Another emerging issues is that the workplace health issues on MeBr fumigation are related with poor ventilation etc as well as well-known phytotoxic damages on them. In previous report, we have evaluated the efficacies of ethyl formate (EF) and phosphine (PH3) on different types of mealybugs. Herein, the phytotoxic damages of EF and PH3 on Alocasia, Sansevieria, Cactaceae and Croton genera were evaluated in terms of chlorophyll contents, color changes etc. This study showed that EF and PH3 fumigation on imported plants could be applicable to replacement of MeBr with further confirmation trials.

Methyl bromide (MB) fumigation is still allowed to use in quarantine treatment on imported timbers and logs, even though IPPC(International Plant Protection Convention) was strongly recommended to reduce their use in case of existing alternatives. A newly developing MB alternative fumigant, ethanedinitrile (EDN), showed the potential in terms of better efficacy to various timber pests and penetration into the timber than MB. Herein, for suggestion of quarantine guideline in Korea, we had verified the efficacies under different temperature conditions(5, 5-15, >15℃) and monitored TLV(Threshold limited value) of EDN post-fumigation for worker safety. The 6 scheduled doses of EDN depending on types of timber pest and temperature conditions had evaluated with PVC-Tarp tent(>100m3) with 40-50% loading factors of imported logs. To control normal wood related pests such as Japanese termite (Reticulitermes speratus) and bark beetle(Cryphalus fulvus), the scheduled doses 30, 40 and 40 g/m3 for 24hr fumigations showed >99% efficacy at 5, 5-15 and >15℃, respectively. The scheduled doses 100, 120 and 150 g/m3 for 24hr fumigations was also successful to gain the proved efficacies at 5, 5-15, >15℃, respectively, for the quarantine guideline to notorious wood related pests such as Japanese pine sawyer (Monochamus alternatus) and pine wilt nematode (Bursaphelenchus xylophilus). The recommended ventilation times with atmospheric conditions at ports was > 1 and > 2 hr under the fully uncovered and partially uncovered of fumigation tent conditions, respectively.

Since Montreal protocol in1989 designated MB(methyl bromide) as ozone depleting chemicals, IPPC(International Plant Protection Convention) has adopted replacing the MB with alternative chemical and reducing the rate of MB use in plant quarantine in 2008. Pineapples are one of the most frequently fumigated imported fruit with MB in Korea. However, there was no technically available replacement. Therefore, we evaluated phosphine(PH3) fumigation as alternative to MB in applying pineapples. In the preliminary test, PH3 gas in 12L desicators to calculate ranged to 0.1 from 2g/m3 was tested at 2 and 24hr exposure to target pest, citrus mealy bug(CMB, Planococcus citri). All different of stage of CMB was shown 100% mortality when 2g/m3 of PH3 applied for 24hrs at 8℃. To confirm studies designed in 0.5m3 fumigation chamber, all egg, nymph and adult stages of CMB was killed completely and there wasn’t any phytotoxic and quality damages on pineapples for 2 weeks post-fumigation periods at 8℃. In terms of commercial use, further commercial research will need to be carry out in cooperation with importers and fumigators.

Methyl bromide (MB) has been banned by Montreal Protocol due to ozone depletion in developed countries since 2005 but uses for quarantine & pre-shipment (QPS) remains exemption. Current MB alternatives such as phosphine gas, ethyl formate has been showing their potential in terms of their no phytotoxic damages to target perishable commodities post fumigation as well as their efficacy at low temperature. We evaluated phosphine (PH3) gas as MB alternatives welsh onion, carrot, and lettuce fumigation. on sensitivity test, larvae of Aphis gossypii were most tolerant to PH3 among the all stage of A. gossypii, Tetranychus urticae and Plutella xylostella. The LC99 and LCT99 value of mixture gas for adult of A. gossypii was 1.79 mg/L (24hr, 5℃) and 33.56 mg h/L(5℃), respectively. On confirmation trials scheduled in 28m3 container for 24hr at 5℃, all stages of T. urticae was completely controlled in 2g/㎥ of phosphine gas, but A. gossypii and M. persicae were not completely controled. No phytotoxic damage was observed in vegetables.

VapormateTM, the new gas formation of ethyl formate(EF) with carbon dioxide, is an MB(methyl bromide) alternative fumigant for grains and perishable commodities especially to control quarantine pest. To gain systematic efficacies of VapormateTM, vaporized gases in Tedlar bag were collected from liquefied gases in cylinder. Vaporized gases were used for collecting efficacy data to Tetranychus urticae, two-spotted spider mite, for 6hr at 26± 1℃. When applied 25, 51, 77 and 102 ml/L of vaporized gas for 6hr, mortality of T. urticae female adult were 83.3, 97.8, 100, and 100%, respectively, at 24hr after fumigation. Also, at 77 and 102 ml/L of vaporized gas for 4hr treatment at 26± 1℃, the mortality of T. urticae female was 96.7 and 97.8%, respectively. This preliminary result may help to understand further scaled-up VapormateTM fumigation applied with different type of commodities.

In Korea, methyl bromide(MeBr) is the only registered fumigant for quarantine application in imported timbers and wood packaging materials to control foreign wood-destroying pest. Under a agreement in the Clean Air Act and the Montreal Protocol to MeBr's ozone depleting properties, the use of MeBr is now strictly restricted and phased out year by year, even though there are exemptions for QPS (Quarantine and Pre-shipment) and CUE (Critical Use Exemption). However, due to increasing of global trades and protection of agro-ecosystem in imported counties against quarantine pests, MeBr in QPS use is increasing (16,304t in 2005, approximately 8.7% increase based on 1996), and domestic consumption of MeBr is recorded up to 938t (annual average among 2003 and 2005), especially the 67% percent (628t) of total MeBr uses imported timber and wood packing materials. Since ethanedinitrile (EDN) was patented by CSIRO in Australia, BOC and Dongbu have tried to develop and commercialize EDN as a timber fumigant. This is updated information on the developmental status of EDN, which included the biological efficacy to target pests and the penetrating aspect to target commodity in the semi-field and various field trials. Based on current results, EDN could replace MeBr for using timber fumigation and would play an important role in the ozone layer protection.