Although ethylformate and phosphine fumigants are widely used for pest quarantine, studies related to their mechanism of action and metabolic physiological changes in Drosophila models are still unclear. In this study, we investigated how key metabolites altered by fumigants and cold treatment are associated with and affect insect physiology by comparative metabolome analysis. Fumigant treatment significantly altered cytochrome P450 and glutathione metabolites involved in the detoxification mechanism and showed lower expression of PGF2α involved in the immune response compared to the control. Additionally, most of the metabolites functioned in metabolic pathways related to the biosynthesis of amino acids, nucleotides and cofactors.

Historically, the control of stored-product insects has mostly relied on the use of fumigants such as methyl bromide (MB) and phosphine. However, methyl bromide is no longer used for structural fumigations, and phosphine insecticide resistance is rising globally. Methyl benzoate (MBe) is a new green pesticide that occurs naturally as a metabolite in plants. In this study, we evaluated the the potential use of MBe as a fumigant against a variety of stored-product insects. According to our laboratory findings, MBe showed strong fumigation toxicity against the Indian meal moth and flat grain beetle with an LC50 value of 0.1 μL/L and 0.76 μL/1.5 L air, respectively, compared to the other tested insects. Furthermore, no significant differences were observed in susceptibility levels between the lab strain and the phosphine-resistant lesser grain borer and rice weevil. However, the red flour beetle had the highest LC50 value of 8.26 μL/1.5 L air. Overall, MBe seems to be a highly promising candidate for the development of environmentally-friendly alternative fumigants.

Spotted wing drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), is an important quarantine insect pest on blueberry and strawberry exportation in Korea. Due to IPPC recommendations of replacement of methyl bromide (MB) and recent critical issue about its chronic inhalation toxicity to fumigator and related workers along with post-fumigation, alternatives to MB is urgently required. Thus, we evaluated efficacies of ethyl formate (EF) to SWD eggs using two different bioassay methods; using eggs oviposited on artificial diet and on blueberries naturally infested with SWD adults. In results, there was no differences between two bioassay methods in terms of LCT99 value of EF.

많은 산림해충들은 목재검역에서 문제가 되고 있어 포스핀(PH3)을 이용하여 광릉긴나무좀, 왕녹나무좀, 노랑애나무좀의 성충에 대한 살충 활성을 조사하였다. 3종의 나무좀류에 대하여 99% 살충활성을 보이는 LCT값은 각각 3.192 (광릉긴나무좀), 0.994 (왕녹나무좀), 0.501 mg ‧ h/L (노랑애나무좀) 순으로 나타났다. 포스핀을 처리한 3종의 나무좀류는 시간이 지남에 따라 살충활성도 증가하였다. 특히 광릉긴나무좀에서 는 0.4 mg/L 이상의 농도에서 약제처리 7일 후에 100%의 사충률을 보였다. 이러한 결과로 볼 때 포스핀이 3종의 목재해충 성충에 대해 메칠브 로마이드의 대체훈증제로 이용될 수 있을 것으로 판단된다.

Carbonyl sulfide(COS) is a naturally generated gas from fermentation process of microbes and from plant root and stem. COS was firstly registered as a fumigant at 1993 to control stored product pests. To supplement environmental problems and toxicity of commercial fumigants and develop new fumigant, we have processed the susceptibility assessment of carbonyl sulfide on important agricultural pests, Myzus persicae and Tetranychus urticae. Every growth stages of two insect species were tested, and five dosages of carbonyl sulfide were treated for 4 hours, and the mortality was investigated after 24 hours of treatment. Nymphal stage of M. persicae was completely controlled at more than 20 mg/L dosage, and adult stage showed 95.8% mortality at 80 mg/L dosage. The LC50 of M. persicae was 7.314mg/L for nymph and 26.117mg/L for adult stage. Egg stage of T. urticae showed 91.2% mortality when treated with 100mg/L carbonyl sulfide, and nymph and adult stage showed 100% and 94.1% mortality at 8mg/L and 80mg/L, respectively. The LC50 of T. urticae was 73.110mg/L for egg, 2.818mg/L for nymph and 12.054mg/L for adult stage.

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.

The susceptibility of the Cigarette beetle, which are pests in tobacco, to methyl bromide and phosphine fumigants was evaluated. Five concentrations of each methyl bromide were selected for all stages and treated for 4 hours. As a result, 100% larvae were observed in eggs CT 51.20, late larva CT 73.61, pupa CT 71.87 and adult 52.87 mg h / L, respectively. The LCT50 values for methyl bromide were 13.896 for eggs, 36.038 for late larvae, 25.172 and 21.758 mg / l, respectively. The phosphine treatment was carried out for 5 to 6 concentrations (0.025, 0.051, 0.099, 0.501, 0.999 and 1.500 mg / L) for 20 hours. As a result, egg and late larvae showed 100% larvae at CT 5.137 and 6.435 mg h / L, respectively, and 61.9% and 98.9% of larvae and adult larvae were similar to each other. Pupae showed 86.4% larvae at CT 10.520 and 100% larvae at over 13.777 mg / h of CT. The LCT50 values for phosphine were 0.317 for eggs, 0.649 for late larvae, 3.748 for pupa and 0.703 mg / l for adults.

Methyl benzoate (MB) is a natural compound in many plants and shows insecticidal toxicity against various insect pests. We determined contact, fumigant, and repellent activities of MB against the sweetpotato whitefly Bemisia tabaci and the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae). Complete contact mortality was obtained by 4% MB. Contact mortality at 2% MB into eggs, 4th instar nymphs and adults were 69.4%, 91.6% and 80%, respectively. Fumigation of 2% MB killed 95% of adults. In addition, treatment of 4% MB repelled 60% adults. There was no significant different between two species. Our results suggest that MB has high potential as an natural pesticide for sustainable pest management in crop production.

Ethyl formate has been used for the control of insect pests by fumigation. However, there were not many reports toshow its target site of fumigant toxicity on insect pests since its first use in the agricultural industry. In the present study,we showed the presumable target sites of ethyl formate fumigation in insect pests using Myzus persicae nymphs. Afterethyl formate fumigation, the nymphs of this species were collected and the changes at the biochemical and molecularlevel were determined. The activity of cytochrome c oxidase (COX) was approximately two-fold higher after ethyl formatefumigation. In addition, the expression levels of acetylcholinesterase (AChE) decreased gradually with increasing ethylformate concentration. These two findings suggested that COX and AChE might be the major target sites of ethyl formatefumigation. In addition to these results, the analysis of lipid content using MALDI-TOF MS/MS identified 9 phospholipidsdifferently generated 2-fold higher in the ethyl formate-treated nymphs than that in the control nymphs, thereby leadingto changes in cell membrane composition in M. persicae nymphs. Therefore, the ethyl formate fumigation caused lethaleffects on M. persicae nymphs by changing COX activity, AChE gene expression, and phospholipid production.

이산화염소 훈증 처리는 저곡해충에 대한 방제 가능성을 가지고 있다. 특히 체내로 독성 가스의 침투력을 높이기 위해 기문의 개방화를 유 도하면 이 훈증 가스 처리 효과를 증가시킬 수 있다. 이 가설을 증명하기 위해 본 연구는 이산화염소 훈증 처리에 감수성을 보이는 화랑곡나방 (Plodia interpunctella)을 대상으로 기문 개방 활동을 분석하였다. 화랑곡나방 유충의 기문은 모두 9쌍으로 앞가슴에 1쌍 그리고 복부에 8쌍을 각 각 지니고 있다. 이들은 몸 내부에 가로 및 세로기관지와 연결된 구조를 지녔다. 기문 개방 유무는 염색액 침투 방법으로 판정하였으며 이를 토대 로 분석한 결과 주변 온도 증가에 따라 기문 개방화는 약 60% 까지 증가하였다. 특히 이산화탄소에 노출되면 기문개방화는 약 95%까지 증가하였 다. 반면에 이산화염소에 노출되면 화랑곡나방 유충의 기문은 대부분 닫혀 기문개방율이 약 25%로 줄었다. 이산화염소 처리에 이산화탄소를 추 가한 결과 기문개방율은 이산화탄소 단독 처리만큼 크게 증가하였다. 이를 토대로 두 혼합 가스를 처리하여 살충효과를 분석한 결과 이산화염소 단독 처리에 비해 혼합처리가 현격하게 높은 살충력을 나타냈다.

In this study, the virucidal efficacy of a fumigant (35% paraformaldehyde) against avian influenza virus (AIV) was examined. After AIV suspensions had been deposited on stainless steel carriers, the dried carriers were exposed to the fumigant in a 300-m3 test room for 3 h. Thereafter, all carriers were submerged in a neutralizing solution to scrape off the surviving viruses, and the respective suspensions were diluted. Each dilution factor was respectively inoculated into the allantoic membrane of five 10-day-old embryos. After incubation, AIV viability in the collected allantoic fluids was examined and the EID50 was calculated. The fumigant inactivated ≥5.7log10EID50 of AIV and was nontoxic to the embryos.

This study was conducted to determine the toxicity to adult Myzus persicae (Sulzer) and Aphis gossypii Glover of 88 plant essential oils and six experimental spray formulations containing bitter orange or marjoram oil was examined using the vapor-phase mortality and spray bioassays. Results were compared with those of two conventional insecticides deltamethrin and dichlorvos. As judged by 24 h LC50 values, bitter orange oil (0.0212 and 0.0192 mg/cm3) was the most active material, followed by marjoram, celeryseed, and cypress oils (0.0239-0.0508 and 0.0209-0.0542 mg/cm3). These essential oils were significantly less toxic than dichlorvos, respectively. These essential oils were consistently more toxic to adult M. persicae in closed versus open containers, indicating that toxicity was achieved mainly through the action of vapor. Bitter orange oil and marjoram oil applied as 1% spray provided complete mortality toward two aphid species adults. Reasonable aphid control in greenhouses can be achieved by a spray formulation containing the 1% oil as potential contact-action fumigant.