• Korean journal of applied entomology
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• v.56 no.3
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• pp.253-259
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• 2017

Fumigation using chlorine dioxide ($ClO_2$) has been regarded as a potential control technique against stored grain insect pests. The control efficacy can be enhanced with increase of opening rates of spiracles by facilitating the toxic gas delivery to internal body. To test this hypothesis, this study used the Indianmeal moth, Plodia interpunctella, which was known to be susceptible to $ClO_2$, and analyzed the opening rate of spiracles. A total of 9 pairs of spiracles were observed in P. interpunctella larvae, in which one pair was located on the prothorax and eight pairs were on the abdomen. Within the body, the spiracles were connected to longitudinal and transverse tracheal trunks. The open spiracles were determined by the dye-infiltration method. Based on this method, the opening rate of spiracles increased up to about 60% with increase of ambient temperatures. Furthermore, exposure to carbon dioxide stimulated the opening rate of spiracles up to about 95%. In contrast, exposure to $ClO_2$ prevented the spiracle opening and resulted in only 25% of spiracles in an opening state. The addition of carbon dioxide to $ClO_2$ treatment rescued the opening rate of spiracles as much as the carbon dioxide single treatment. Based on this modulatory activity of carbon dioxide against spiracles, the combined treatment of $ClO_2$ with carbon dioxide resulted in significant increase of its toxicity against P. interpunctella compared to a single $ClO_2$ treatment.

• Korean journal of applied entomology
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• v.58 no.4
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• pp.341-345
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• 2019

Ethyl formate (EF) is a rapid kill, environmentally safe, and low mammalian toxicity fumigant, registered to disinfest quarantine insect pests from imported agricultural products. A new concept for controlling insect pests of agricultural crops was tested in a fumigation chamber with EF. Control efficacy of and phyto-toxicity due to EF fumigation were evaluated against four pests (Thrips palmi, Bemisia tabaci, Myzus persicae, and Tetranychus urticae) and on seedlings of four fruit vegetables (FVs; yellow melon, cucumber, tomato, and pepper). Ethyl formate fumigation at a dose of 1.5 g m^-3 for 12 h produced >93.3% mortality in T. palmi, B. tabaci, and M. persicae. However, T. urticae was tolerant to fumigation, showing only 20% mortality at 2.0 g m^-3. In terms of concentration × time (CT) products, at least 8.9 g·h m^-3 CT at 20 ± 1.5℃ was needed to achieve > 90% mortality against the three susceptible insect pests. Fumigation at 1.5 g m^-3 for 12 h caused no phyto-toxicity to any of the four FV seedlings. Ethyl formate application, as a new disinfestation method in greenhouses, could be an alternative to reduce the use of conventional insecticides. However, further studies are needed to determine the efficacy of this method at different pest developmental stages and in different greenhouse environments. Additionally, research is needed to elucidate the phyto-toxicity of EF application at different growing stages of a wide variety of crops.

• Korean journal of applied entomology
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• v.25 no.3 s.68
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• pp.169-173
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• 1986

Ginseng fields abolished by potato rot nematode (Ditylenchus destructor) (heavily infested with the nematode) were treated with selected nematicides after preplanting treatment with fumigants or non fumigant chemicals in the fall of 1982. Suppression of the nematode populations was noted in the fields fumigated by cylon (Cy) and treated with ethoprop (E) or triazophos (T). Also in these treatments, high percentages of shoot sprouting and low nematode damages were observed. In the fields fumigated by Cy, subsequent treatments with nonfumigant nematicides such as E, aldicarb (A), phenamiphos (Ph), oxamyl (O) and carbofuran (C) during cultivation had no effect on the significant decrease of the nematode, compared with Cy alone. No differences in shoot sprouting and symptom appearance were observed; however, survivalities of plants and root weights of 4-year old ginseng were high in A and E or E following preplanting treatment with E. Correlation coefficients of the nematode densities to host responses such as sprouting of shoots, symptom appearance, survivality of plants and weight of 4-year old ginseng roots were significant at and mostly before and after the time periods of survey.

• Food Science and Preservation
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• v.12 no.1
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• pp.48-53
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• 2005

Comparative effects between commercial fumigation (methyl bromide/MeBr, phosphine $gas/PH_3$) and gamma irradiation (5, 10 kGy) on dried red pepper were investigated in terms of it microbiological quality, moisture content Hunter's colors, and UV-visible spectra during storage for 8 months at mom temperature. The non-treated control samples showed total aerobic bacteria as $4.8\times10^5\;CFU/g$ in powdered state and $1.8\times10^2\;CFU/g$ in whole red repper. While yeasts and molds were $1.7\times10^5\;CFU/g$ in powdered pepper and $5.0\times10^2\;CFU/g$ in whole pepper, respectively. The effect of chemical fumigant on microbial decontamination was negligible, whereas irradiation at 5 kGy was proven to reduce the microbial populations by 2 to 3 log cycles that could improve the hygienic quality of powdered pepper. Moisture content of the samples showed no noticeable changes resulting 1mm irradiation or fumigation. Immediately after treatments, irradiation or fumigation reduced Hunter's lightness (L), redness (a), and yellowness (b) of the samples (p<0.05), but there was no difference in color parameters between the control and all treated stoups after 4 months of storage. It was found that storage period was more influential than irradiation or fumigation to changes in moisture and color of dried red pepper and ie powder.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.212-216
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• 1981

This experiment was carried out to investigate the penetration velocity and diffusion ability of methyl bromide fumigants under the condition of natural gravity, and the effect of in control of yellow corn in the vortical silo. The results were as fallows 1. The methyl bromide remainded concentration on the surface of the vertical silo was rapidly reduced from over 100mg/l to under 20mg/l, within 2 hours after supplying methyl bromide fumigant 2. Even 3m depth place from the surface of the vertical silo filled with yellolw corn was well penetrated within 30 minutes, but its remained methyl bromide gas was reduced gradually from over 100mg/l to 30mg/l after 12 hours duration. 5. In case of 13m place tile penetration ability of methyl bromide was over 100mg/l within one hour and kept the same concentration of it for 12 hours, its remainded methyl bromide preserved over 40mg/l until 48 duration time. 4. Less methyl bromide gas was detected at the bottom place than 3m and 13m depth of the vertical silo. It showed bellow 20mg/l of methyl bromide gas only through the whole duration time. 5. Comparing to the vertical penetration velocity of mehtyl bromide gas, the horizontal diffusion ability was not so good. Therefore, remained methyl bromide gas of 3m depth at the wall side of silo was about half than that of center circle where the nearer place from the methyl bromide supplying point, and the methyl bromide gas of 13m depth placed center circle was detected about 15 to 20 times than that of wall side. 6. For the purpose of examining the mortality of methyl bromide, the testing insects (Lesser Rice weevil and confused flour beetle) placed on the surface and bottom side of the silo were killed completely after 24 hrs fumigation, and the same results showed also at the 3m, 7m and 13m depth after 48 hrs fumigation.

• Journal of Food Hygiene and Safety
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• v.4 no.2
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• pp.119-132
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• 1989

Gamma irradiation as a new physical treatment was applied to comparative investigates with a conventional ethylene oxide fumigant on the microbiological and physicochemical qualities of selected spices and dry vegetables such as powdered red pepper, black pepper, welsh onion, onion, garlic, carrot, korean cabbage and instant ramyon soup. The microorganisms contaminated in the sample, including total viable count, thermophilic bacteria, aerobic spore and fungi counts between the $10^4\;to\;10^6/g$ range. Coliforms were found only in black pepper and welsh onion powder as the $10^2\;to\;10^3/g$ level. A radiation dose of 7 to 10 KGy were sterilized completely to the contaminated microorganisms, while ehthylene oxide (E.O.) fumigation reduced of them to the $10^3/g$ level. An optimum dose of irradiation was less detrimental than E.O. fumigation to the physicochemical properties of the sample. Sensory evaluation after three months of storage at room temperatures showed that the overall acceptability of irradiated sample was higher than that of the non treated control as well as E.O. fumigated samples. Comparison gamma irradiation with E.O. gas treatment showed that E.O. treatment was less effective than radiation in cotrolling microbial contamination of spices and vegetables.