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Subject: search.filters.subject.Fumigation

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    The use of ozone for controlling european house dust mite, dermatophagoides pteronyssinus (Trouessart)
    (2020-09-01)
    Pumnuan, Jarongsak
    ;
    Insung, Ammorn
    ;
    Wangapai, Teerapong
    Hypersensitivity allergies are mostly caused by house dust mite (HDM), Dermatophagoides pteronyssinus (Trouessart). Common control methods for HDM include disposal of bedding sets and fabrics, vacuuming, washing, using plant extracts and applying chemicals. Hence, the application of ozone is a new alternative way to control HDM. The objectives of this experiment were to determine the efficacy of ozone as an HDM killer and to evaluate the allergic levels that remained after the application of ozone. The fumigation method was performed in a laboratory using ozone at the concentrations of 20, 30, 40 and 50 mg l-1 in glass chambers (1 m3) at 1, 2 and 3 h fumigation intervals. The mortality percentages of HDM were observed at 24 h after the treatment. The allergic levels appearing in supernatants were analyzed by an enzyme-linked immunosorbent assay (ELISA) method. Ozone fumigations of 30 mg l-1 concentration for 3 h completely killed HDM. In addition, ozone fumigations of ≥ 40 mg l-1 for 3 h reduced the amount of allergen by >50%, which was a significantly higher reduction than seen at 20-30 mg l-1 (35.8-45.8%). The study suggests the ozone fumigation at 30 mg l-1 concentration treated for at least 3 h, 40 mg l-1 for 2 h, or 50 mg l-1 for 1 h could be used as a new alternative method to control HDM.
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    Effective microbial disinfection in food industry with hydroxyl radical fumigation
    (2020-01-01)
    Sangadkit, W.
    ;
    Kongtrub, J.
    Hydrogen peroxide (H<inf>2</inf>O<inf>2</inf>) fumigation has recently been explored and tested to be a good fumigant replacement of formaldehyde. This technique has been proven safer, less irritating and requires shorter exposure times. Surface disinfection has long been implemented with toxic formaldehyde or 35% hydrogen peroxide (H<inf>2</inf>O<inf>2</inf>). The results showed that they could be replaced with a safer and stronger oxidizing agent, activated H<inf>2</inf>O<inf>2</inf> in a vaporized form. Aerosolization by aerosol generators has been used to produce aerosols containing hydroxyl radicals of hydrogen peroxide. The dispersal of this highly oxidizing mist of micron-size droplets destroyed Escherichia coli and Aspergillus niger colonies that have been artificially spiked on surfaces. The experiments demonstrated efficient disinfection by integrating 1 to 5% H<inf>2</inf>O<inf>2</inf> fumigation with ozone (O<inf>3</inf>) and ultraviolet light (UV-C). Studies with E. coli and A. niger showed some disinfection with either O<inf>3</inf> or UV-C. Combining H<inf>2</inf>O<inf>2</inf> fumigation with both O<inf>3</inf> and UV-C exposure considerably accelerated the microbial inactivation. This approach allowed fast disinfection with 1 to 5% H<inf>2</inf>O<inf>2</inf> while offering cheaper and safer disinfection for healthcare settings.
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    Insecticidal activity of essential oil formulas and their physiological effects on eggplant
    (2017-05-01)
    Pumnuan, Jarongsak
    ;
    Khurnpoon, Lampan
    ;
    Insung, Ammorn
    This study examined fumigation toxicity of 18 medicinal plant essential oils (EOs) against adult of aphid (Aphid gossypii) and whitefly (Bemisia tabaci). Then, non-target effects of the EO mixtures on physiological changes of eggplant (Solanum melongena) were tested. The insecticidal property and physiological toxicity of the fumigation formulas were also examined and compared to methyl bromide (MB) fumigation. The results showed that the eggplant fumigated with clove (Syzygium aromaticum) and lemon grass (Cymbopogon citratus) EOs mixture at the ratio of 1:3 (Cl1Le3) showed no significant physiological changes when compared to the control treatment. The formula resulted in similarly high mortalities (82-100%) of both insects when compared to MB. However, MB fumigation caused complete senescence appeared before day 3 observations. On the contrary, the eggplant fumigated with Cl1Le3 at 3 μL/L air showed no differences in the physiological changes when compared to the control throughout the 9-day examinations.
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    Effects of insecticidal essential oil fumigations on physiological changes in cut Dendrobium sonia orchid flower
    (2015-09-01)
    Pumnuan, Jarongsak
    ;
    Khurnpoon, Lampan
    ;
    Insung, Ammorn
    This study investigated essential oil (EO) formulas with high insecticidal properties, but low physiological impacts on cut Dendrobium Sonia orchid flower. Fumigation toxicities of EOs from 18 medicinal plants at 2.0 and 3.0 μl/L air were examined against adults of thrips (Frankliniella schultzei) and larvae of mealybug (Pseudococcus jackbeardsleyi). The effective EO mixtures, optimal concentrations fumigation and air circulation periods were investigated. Then, field experiments were conducted, and changes in L*, a* and b* values, percentages of weight loss and anthocyanin contents of the EO-fumigated flower were observed and compared to the methyl bromide and control fumigations. The results showed that clove and cinnamon demonstrated high insecticidal properties against the insects (>85% mortality) and low physiological changes in the flower. In particular, fumigations with 2.0 μl/L air of a mixture between clove and cinnamon EOs (1:3) for 3 hr with 15- min air circulation demonstrated the highest thrips and mealybug mortalities (92.2 and 74.6%, respectively). The EO fumigation formula presented less impact on color change and anthocyanin content than methyl bromide fumigation which showed higher reduction of anthocyanin content (22.9 mg/100g FW) when compared to the control (13.6 mg/100g FW). The percentages of weight loss in the flower fumigated with EO, control and methyl bromide were about 10.4, 7.9 and 14.8%, respectively. In general, applications of EO at higher concentrations resulted in higher insect mortalities and more impacts on physiological changes which involved anthocyanin degradation and higher percentages of weight loss. Further studies might consider applications of clove and cinnamon EO formulas via other methods. In addition, revisions of the EO mixture can also be examined in order to obtain the most effective and environment friendly insect management approach.