Methyl bromide (MB) has been still routinely used in quarantine fumigation on imported citrus, although there had been issuing chronic inhalation toxicity to fumigators and related workers as well as phytotoxic damages after fumigation. Ethyl formate (EF), is the only option to replace MB in terms of its safety for consumers (food additive and naturally occurred) and worker with higher threshold level limit (TLV = 100 ppm). Its application technology also provide cost effectiveness, good commercial practice in terms of application time (< 10 min) for 40 ft container. The replacement of MB with EF is recommended not to fumigate with hazardous and phasing-out MB on imported oranges.

To replace hazardous methyl bromide (MB) post-fumigation on imported fruits, due to insufficient ventilation process in industrial practice, alternative fumigation with liquid ethyl formate (EF) with N2 application, which is multi benefits to safe to workplace and environment, has been developed by APQA. Although EF was found to be shown proven efficacy to invasive external feeders such as mealybugs and scales on export and imported fruits and vegetables, there was still some conflicts to accept one of the phytosanitary disinfestation method somewhere because of on reliable and confirmative studies on between MB and EF in terms of efficacy to mealybugs on perishable commodities. In here, we evaluated comparative efficacy of EF and MB to target citrus mealybug, which was seems to be hard control pest, based on the current disinfestation guideline of them in Korea. The potential benefits of using liquid ethyl formate (EF) for future quarantine use could provide for safer workplace involved on and post-fumigation such as cold and packing storages, cost-effectiveness as well as meet the environmental friendly solution.

The respiration rate of PH3 susceptible strain was significantly higher than the resistant strain. The results showed no significant effect of oxygen level on the respiration rate of both strains. Phosphine reduced the respiration rate of both strains when it was applied in average concentrations. However, the rate of respiration of the resistant beetles increased significantly under a high level of phosphine. The increase of respiration rate was associated with the higher emission of VOCs which prove the acceleration of metabolic processes to face the phosphine action for survival. Flat grain beetle Cryptolestes pusillus and rusty grain beetle C. ferrugineus are similar insect species, but only C. ferrugineus is capable to develop a high phosphine resistance. A direct immersion solid phase microextraction gas chromatography-mass spectrometry (DI-SPME-GCMS) technology has identified the different fatty acids from PH3 resistant and susceptible strain of Tribolium castaneum.

Fumigation - one of the chemical methods - is the art of dispensing and applying gaseous substances especially for the purpose of disinfecting. It is an old and widely used technique for disinfestation of postharvest grain, fruit and vegetable. In a fumigation procedure, a gas is added to an enclosure for the purpose of controlling or eliminating undesirable organisms. The organisms may be pests of various types - such as insects, rodents, mites, and birds - or micro-organisms, or particular plants or seeds. The enclosure can be made from a diverse range of materials, including metal, concrete, bricks, mud and various plastic membranes. It is necessary to contain the fumigant while it acts on the target organism and to restrict its escape into areas where it may be dangerous to human health. In many situations fumigation may be the only feasible process for pest control as it does not require the commodity to be moved. Neither might it need specialized apparatuses, electricity, or manpower, and is relatively easy to apply in comparison with other methods, for example, heating and irradiation, as well as the use of protectants to control insects. Because fumigation is often the cheapest and most effective process available, it plays a major, world-wide, role in preserving commodities. However, researchers and operators not always fully understand principle of fumigant and fumigation practice to ensure select right fumigant and exposure time on different target insect pests and host commodities as well as application methods.