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1.
集装箱溴甲烷熏蒸散气速率的试验研究表明:集装箱熏蒸后残余溴甲烷的浓度和散气时间、货物的吸附、集装箱内货物的容量有关,与温度、天气状况以及不同规格集装箱关系不显著;通过自然散气8h和3周左右的航行时间就能到达残留低于5ppm(20mg/m3)的要求,但对于装载溴甲烷气体强吸附性的货物、用塑料袋包裹的货物或集装箱装载量过满的货物,应延长散气时间或采取机械协助通风来控制残余气体浓度.  相似文献   

2.
N. Ioannou 《Phytoparasitica》2000,28(3):248-256
Preplant soil fumigation with methyl bromide (MB) is presently standard practice in greenhouse tomato production. Since this compound is scheduled to be phased out by 2005, the possibility of using solarization as an alternative soil disinfestation method was examined in four greenhouse tomato trials. Solarization was applied for 8 weeks in July-August, using transparent polyethylene sheets for soil mulching, and compared with MB fumigation applied in September, before planting, at 80 g/m2. Solarization raised the maximum soil temperature by 9°C and reduced the population density ofFusarium spp. in soil by 91–98%. Similar reductions of soil inoculum (95–99%) were obtained with MB fumigation. Both methods provided effective control of Fusarium wilt, Verticillium wilt and corky root rot on tomato plants. MB fumigation was in addition highly effective against root-knot nematodes, whereas nematode control with solarization did not exceed 50%. Both treatments resulted in similar fruit yield increases, ranging within 90–140% compared with plants grown in untreated soil. During the second cropping season following soil treatment, solarization exhibited two times higher residual effectiveness against vascular wilt diseases compared with MB fumigation. The latter treatment, however, was superior to solarization in its residual effectiveness against root-knot nematodes and to a lesser extent against corky root rot. Fruit yields from solarized and MB-fumigated soil during the second cropping season were higher than those obtained from untreated soil by approximately 35% and 60%, respectively. In Cyprus, solarization appears to be an effective alternative to MB fumigation in greenhouse tomato production, especially if integrated with other approaches enabling more effective nematode control.  相似文献   

3.
The persistence of methyl bromide (MB) in white rice, brown rice, sultanas, raisins, pumpkin seeds, brazil nuts, groundnuts and walnuts was monitored following laboratory fumigations at different concentration time products and temperatures. A sensitive automated headspace gas chromatographic method with a limit of quantitation of 0.005 mg kg−1 was used to determine MB residues. Nuts and seeds sorbed the highest amounts of MB followed by rice and dried fruit. Measurable MB residues were shown to persist in nuts and seeds for 10 weeks and in dried fruit for four weeks following a fumigation with recommended concentration time products. The data presented suggest MB residues may persist in unprocessed nuts, seeds or dried fruit at the point of consumption using recommended fumigation practices, or particularly following overdosing or multiple fumigations. Crown copyright © 2000 Reproduced with the permission of Her Majesty's Stationery Office  相似文献   

4.
The rate of gas interchange between the atmosphere within a freight container and the external air has an important influence on the effectiveness of in-container fumigation. When a container is exposed to the wind or is in motion, the rate of gas interchange may be much greater than that under static conditions. The effect of motion or wind on gas interchange was studied by observing gas loss from freight containers, both empty and loaded with rice, while stationary and while being transported by rail. The gas interchange rate was determined by measuring the rate of loss from the containers of either a combination of a fumigant, methyl bromide, and a relatively inert tracer gas, carbon monoxide, or of carbon monoxide alone. In loaded containers the difference between the loss rate constants of methyl bromide and carbon monoxide (0.29.0.03d?1) was within the range expected for the reaction of methyl bromide with rice. After allowing for gas loss caused by changes in temperature and pressure, the component of the interchange rate constant attributable to air motion was found to be proportional to gas-tightness as measured by a steady-state pressure test, and also to the relative air speed over the container. Under conditions of varying wind and train speed, the fraction of the initial concentration of gas remaining was found to be an exponential function of wind run past the container. When wind effects were not important, it was found to be an exponential function of distance travelled.  相似文献   

5.
减压条件下溴甲烷对松褐天牛熏蒸效果的研究   总被引:1,自引:0,他引:1  
利用XMG-35真空熏蒸库在11~21℃和减压条件下,选择不同压力和浓度梯度,对含有松褐天牛(Monochamus alternatus Hope)幼虫的黑松(Pinus thunbergii)木段进行4h的溴甲烷熏蒸处理,投药后循环20min,将库内气压立即回升至95kPa。结果表明,松褐天牛幼虫的杀灭效果和环境温度、压力、投药剂量有关,在其他条件相同的情况下,压力越低,对松褐天牛的杀灭效果越好;在相同条件下,保持30kPa状态20min再将气压缓慢回升至95kPa,对松褐天牛的杀灭效果介于常压熏蒸与减压后快速回压熏蒸之间。  相似文献   

6.
为明确溴甲烷和硫酰氟对捆包苜蓿草的熏蒸穿透效果,本文分别使用溴甲烷和硫酰氟对捆包苜蓿草进行了帐幕熏蒸,并研究了2种熏蒸剂在苜蓿草不同深度内的穿透。结果表明,随熏蒸进行,2种熏蒸剂均可逐渐穿透到捆包苜蓿草内部(60 cm深度),其中溴甲烷完全穿透至60 cm深度的时间为24 h,高浓度熏蒸48 h后,苜蓿草内部20 cm、40 cm和60 cm处的溴甲烷浓度仍仅有外部空间的77.3%、57.8%、56.2%;硫酰氟完全穿透60 cm深度的时间为8~12 h,高浓度熏蒸48 h后,20 cm、40 cm、60 cm深度内的硫酰氟浓度分别是空间硫酰氟浓度的102.2%、101.8%、97.2%,苜蓿草内部硫酰氟浓度与外部空间浓度基本达到平衡。这些结果表明,硫酰氟熏蒸对进境捆包苜蓿草的穿透力强于溴甲烷。  相似文献   

7.
Methyl bromide fumigations are used to treat apples, Malus domestica Borkh, and sweet cherries, Prunus avium (L), before export to Japan. In order to expand existing markets, additional cultivars are being prepared for export to Japan. As part of the approval process, residue analyses must be conducted and residues must be at acceptable levels. Five apple cultivars (‘Braeburn,’ ‘Fuji,’ ‘Gala,’ ‘Jonagold,’ and ‘Granny Smith’) were fumigated at 40 g m−3 for 2 h at 10 °C, and six sweet cherry cultivars (‘Brooks,’ ‘Garnet,’ ‘Lapin,’ ‘Rainier,’ ‘Sweetheart,’ and ‘Tulare’) were fumigated for 2 h with 64 g m−3 at 6 °C, 48 g m−3 at 12 °C, 40 g m−3 at 17 °C, and 32 g m−3 at 22 °C. Three replicates of fruit from each fumigation were analyzed for methyl bromide and bromide ion residues periodically with time. Methyl bromide residues for both apples and cherries were the highest immediately after fumigation, but rapidly declined so that only ‘Braeburn’ had residues >8 µg kg−1 after 13 days and, except for ‘Lapin,’ all cherries were <1 µg kg−1 after seven days. Average bromide ion residues were between 3.3 and 4.9 mg kg−1 among apple cultivars, and between 3.7 and 8.0 µg kg−1 among cherry cultivars. Published in 2000 for SCI by John Wiley & Sons, Ltd  相似文献   

8.
本文研究了磷化氢(PH3)和溴甲烷(MB)复合熏蒸对番石榴实蝇的毒力以及对红心火龙果采后品质的影响。结果表明,复合熏蒸方式下,各个浓度的磷化氢和溴甲烷均存在增效,当溴甲烷浓度为4 g/m3时,复合熏蒸发挥最佳增效效果的磷化氢浓度为1.42 g/m3。复合熏蒸番石榴实蝇仅需13.19 g/m3的溴甲烷即可在95%置信区间下达到致死率99.996 8%。与对照相比,复合熏蒸对火龙果的外观和内部品质无显著影响,而与溴甲烷单独熏蒸相比,复合处理会显著降低呼吸强度并减少药害。因此,溴甲烷和磷化氢复合处理对番石榴实蝇具有协同效应,表明磷化氢和溴甲烷复合熏蒸有可能成为水果采后处理的一种新策略。  相似文献   

9.
苹果是我国的重要出口水果,山楂叶螨(Tetranychus viennensis Zacher)和桃蛀果蛾(Carposinasasakii Matsumura)在苹果主产区广泛分布,严重威胁我国苹果出口。为确定溴甲烷检疫处理山楂叶螨和桃蛀果蛾的技术指标,本文系统测定了一系列温度条件下溴甲烷对山楂叶螨成螨和富士苹果中桃蛀果蛾老熟幼虫的毒力,确定在5℃、10℃、15℃、20℃和25℃下,溴甲烷熏蒸山楂叶螨死亡率达到机率值9所需浓度时间乘积(CT值)分别为126.66、84.35、59.15、45.23和40.33mg.h/L,溴甲烷熏蒸桃蛀果蛾死亡率达到机率值9所需CT值分别为128.05、81.80、52.91、41.56和36.43mg.h/L。根据上述结果,建议采用10.0~14.9℃40g/m3 2h、15.0~19.9℃32g/m3 2h、20.0~24.9℃24g/m3 2h和大于25.0℃20g/m3 2h作为出口苹果的溴甲烷熏蒸处理技术指标。  相似文献   

10.
真空情况下,利用溴甲烷、环氧乙烷杀虫、灭菌是一种安全、快速、有效的技术措施。为了使此技术广泛应用到农林种子、苗木、卫生防疫以及文史资料诸方面杀虫灭菌,试制成功一台容积工立方米的PCV-1000程序控制真空熏蒸机,并进一步进行溴甲烷、环氧乙烷杀虫灭菌效果及其熏蒸后残余毒气处理方法的研究。溴甲烷75—90克/立方米处理2小时,环氧乙烷90—120克/立方米处理3小时,可杀死各种形式的包装内的谷斑皮蠹和花斑皮蠹幼虫,赤拟谷盗和锈扁谷盗成虫以及玉米象和绿豆象各虫态等害虫。环氧乙烷灭菌能力较强,对动物炭疽菌、4001芽孢杆菌500克/立方米处理5小时或300克/立方米处理12小时,灭菌效果100%。溴甲烷和环氧乙烷混合使用对棉花枯萎病菌效果良好,对棉籽发芽率影响不大。熏蒸后残余毒气处理,用5%氢氧化钠酒精液吸收溴甲烷,破坏率可达96%以上。环氧乙烷用自来水淋洗法,水合分解率可达98%以上。  相似文献   

11.
BACKGROUND: Many California grape growers use preplant fumigation to ensure uniform and healthy grapevine establishment in replant situations. A field study was conducted to evaluate the performance of subsurface drip‐applied chemical alternatives to methyl bromide on plant‐parasitic nematodes, plant vigor and fruit yield during the 6 year period following replanting. RESULTS: Subsurface drip fumigation with 1,3‐dichloropropene plus chloropicrin and with iodomethane plus chloropicrin had generally similar nematicide activity as methyl bromide in three grape types, while sodium azide was less effective. The combination of 1,3‐dichloropropene plus chloropicrin enhanced vine vigor similarly to methyl bromide. However, all plots treated with alternative fumigants produced less fruit yield than methyl bromide over the 4 years of evaluation. CONCLUSION: Subsurface drip fumigation with alternative chemicals to methyl bromide generally provided adequate management of plant‐parasitic nematodes during the vine establishment period. However, further research is required to increase the performance of alternative chemicals against other components of the replant problem, as grape yield in vines grown in the alternative treatments was lower than in methyl bromide. Copyright © 2011 Society of Chemical Industry  相似文献   

12.
BACKGROUND: Producers of perennial crop nursery stock in California use preplant soil fumigation to meet state phytosanitary requirements. Although methyl bromide (MB) has been phased out in many agricultural industries, it is still the preferred treatment in the perennial nursery industry and is used under Critical Use Exemptions and Quarantine/Preshipment provisions of the Montreal Protocol. The present research was conducted to evaluate reduced‐rate MB applications sealed with conventional and low‐permeability plastic films compared with the primary alternative material. RESULTS: Reduced rates (100–260 kg ha?1) of MB applied in combination with chloropicrin (Pic) and sealed with a low‐permeability plastic film provided weed and nematode control similar to the industry standard rate of 392 kg ha?1 MB:Pic (98:2) sealed with high‐density polyethylene (HDPE) film. However, the primary alternative chemical, 1,3‐dichloropropene (1,3‐D), tended to provide slightly lower pest control even on sites with relatively low plant parasitic nematode, soil‐borne pathogen and weed pest pressure. CONCLUSION: If California regulations change to allow the use of low‐permeability films in broadcast fumigant applications, the results of this research suggest that reduced rates of MB in perennial crop nurseries could serve as a bridge strategy until more technically, economically and environmentally acceptable alternatives are developed. Published 2010 by John Wiley & Sons, Ltd.  相似文献   

13.
BACKGROUND: Ethyl formate formulations are being considered to replace methyl bromide for fast grain disinfestation. Grain adsorbs ethyl formate rapidly, which can result in inadequate fumigation concentrations and unacceptable grain residues. A model of ethyl formate sorption kinetics will enable fumigation approaches to be determined that meet disinfestation and food safety requirements. RESULTS: This paper identifies all mass transport processes involved in ethyl formate sorption by wheat from published and experimental evidence. The model accounts for reaction losses of ethyl formate in air and grain using first‐order kinetics, transport in the gas and solid phases with linear mass transfer coefficients and uses a linear partition relationship representation of sorption equilibrium. Batch experimental data were measured to determine model coefficients. Novel gaseous breakdown data for ethyl formate in air were measured, and first‐order kinetics was demonstrated, although the specific reactions involved were not identified. CONCLUSION: The model predicts air and grain fumigant concentrations relevant for grain disinfestation and food residue contamination successfully. The form of the model should be applicable to all fumigant–grain systems, as it accounts for the diffusion and reaction influences known to occur with all modern fumigants under concentration and exposure conditions relevant to industry. Copyright © 2009 CSIRO, Australia. Published by John Wiley & Sons, Ltd.  相似文献   

14.
Individual cuttings and leaves of chrysanthemum infested with eggs and larvae of the alien leaf miner Liriomyza trifolii (Burgess) and batches of pupae, were treated in the laboratory in order to find an effective quarantine treatment to control the pest in imported cuttings. Cold treatment for 2 days at 1–2°C followed by methyl bromide fumigation at 15°C with a range of concentration time products (CTPs) was used to obtain accurate dose-response lines and estimate the LD99 and LD99.9 for each stage of the insect. The largest estimates of the LD99 for eggs, larvae and pupae up to 3 days old were less than the CTP specified in the existing (as at September 1983) United Kingdom statutory fumigation treatment designed to prevent the entry of Spodoptera littoralis (Boisd.). This statutory schedule for unrooted cuttings consists of cold storage for 2 days at 1–2°C and then fumigation with methyl bromide at a CTP of not less than 54 g·h/m3 with a minimum treatment period of 4 h at a minimum air temperature of 15°C. Our results indicate that the Spodoptera treatment should give high levels of kill for most stages of L. trifolii provided a CTP of 54 g·h/m3 and a temperature of 15°C (throughout the fumigation) arc achieved uniformly within packs of cuttings when they are fumigated in their transit boxes in commercial practice. The practicality of the technique will depend on whether it is possible to achieve this without causing unacceptable phytotoxicity. The LD99 values for pupae more than 3 days old were greater than those for eggs, larvae and young pupae. Therefore, if this treatment were adopted as a quarantine measure against L. trifolii, good prophylactic treatments and rigorous prc-packing inspections in exporting countries would still need to be maintained, to minimize any risk of importing pupae. The results are presented in full by Mortimer E.A. & Powell, D.F. (1984). Development of a combined cold storage and methyl bromide fumigation treatment to control the American serpentine leaf miner Liriomyza trifolii (Diptera: Agromyzidae) in imported chrysanthemum cuttings. Annals of Applied Biology 105 , (3), 443–454.  相似文献   

15.
Toxicity of methyl bromide to soil-borne fungi   总被引:1,自引:0,他引:1  
Nineteen fungal isolates, mostly plant pathogens cultured on agar, were subjected to fumigation with methyl bromide at known concentration x time product (CTP, concentration in mg/1 x time in h) in a fumigation chamber at controlled temperature. Survival of the fungi was determined by sub-culturing on fresh agar. An order of methyl bromide tolerance of the fungi was cetermined and it was shown that at low concentrations of the fumigant, prolonged exposure, to give a normally toxic CTP, did not kill important soil-borne pathogens. The implication of this in relation to field fumigations is discussed.  相似文献   

16.
Heat treatment of dates at the time of harvest, was examined as an alternative to fumigation with methyl bromide, which has been phased out in Israel under the Montreal Protocol. In laboratory studies, the influence of 40°, 45°, 50° and 55°C on the levels of disinfestation and mortality ofCarpophilus hemipterus larvae was examined over a 2-h exposure period. The ratio of the number of insects found outside the feeding sites to the total number of insects, was greatest at 50°C (92.3%), significantly greater than at 40° and 55°C. At 50° and 55°C, 100% mortality was obtained. Since drying temperatures for most date varieties is between 45° and 50°C, and because percent disinfestation and control was most effective at 50°C, these findings were examined under field conditions. Field trials were carried out at a commercial drying station where the crated dates are placed on the ground inside a plastic-clad hothouse. The stacks were covered with plastic liners to form ‘drying ducts’ through which heated air was sucked using fans positioned at the opposite end of the ducts. It was shown that from 1 to 2 h were required for the dates to reach the set temperature of 50°C. During the following 2-h aeration, the dates were exposed to 50°C heated air, after which an examination of infested dates inserted into the drying ducts, and natural infestations showed that successful control and emigration were obtained. This method produced results comparable to those obtained with methyl bromide fumigation, and was suitable as a replacement technology for infestation control. http://www.phytoparasitica.org posting Nov. 7, 2005.  相似文献   

17.
Efficacy of soil fumigation with methyl bromide and methyl iodide against Botrytis cinerea, Colletotrichum gloeosporioides, Fusarium oxysporum, Gliocladium virens, Phytophthora citricola, Phytophthora citrophthora, Pythium ultimum, Rhizoctonia solani and Verticillium dahliae was determined in laboratory experiments in closed fumigation chambers. Pythium ultimum was the most sensitive fungal species with EC50 values for methyl bromide and methyl iodide of 15.5 and 8.6 µM , respectively. R solani was the least sensitive with EC50 values of 253.4 and 161.4 µM for methyl bromide and methyl iodide, respectively. Relative potency ([methyl bromide]/[methyl iodide]) values ranged from 5.2 for P citricola to 1.5 for F oxysporum. Methyl iodide was 2.7 more efficacious than methyl bromide averaged over all fungal species. Methyl bromide/chloropicrin and methyl iodide/chloropicrin applied jointly were 2.2 and 2.8 times more efficacious, respectively, against F oxysporum than when the compounds were applied singly. Combining methyl bromide and methyl iodide with chloropicrin resulted in a significant synergistic increase in activity against F oxysporum. © 2000 Society of Chemical Industry  相似文献   

18.
19.
A simulation model is described for the transport of the fumigant, methyl bromide gas, away from injection chisels within the field. The injected methyl bromide is assumed to form cylindrical, parallel sources at the depth of injection. Transport of the methyl bromide is described by radial diffusion from the injection cylinders. The dissolution-distillation of methyl bromide gas in the soil water and on soil particles is accounted for by a first-order reversible kinetic equation or by an equilibrium relationship. The hydrolysis of methyl bromide gas to bromide anion is considered to occur according to a first-order irreversible equation. The model considers cases where the soil surface is and is not covered with an impermeable barrier to the diffusion of the gas. Simulated methyl bromide concentrations in the soil air, and bromide concentrations in the soil, compared reasonably well with measured values from several field sites. Comparison of the results of calculations, with and without plastic barriers at the soil surface, with experimental data, indicate that plastic barriers are ineffective in preventing diffusion of gas from the soil to the atmosphere. Calculations of mass balances show that as much as 70% of the applied methyl bromide had escaped to the atmosphere by 14 days after fumigation.  相似文献   

20.
几种常见花卉在真空条件下对溴甲烷耐药性的研究   总被引:1,自引:1,他引:1  
本试验选择了19种常见的草本和木本花卉进行了在真空条件下对溴甲烷的耐药性试验.结果表明,美女樱、天门冬、孔雀草、彩叶草、鸡冠花、含羞草、茉莉、栀子等均表现出对溴甲烷具有良好的耐药性,而月季、万寿菊、矮牵牛、小菊花、榕树、玉树、杜鹃等则表现出轻度的药害症状,对千日红、地肤、小丽花、一串红等的品质和生长有很大的影响,表现为强烈的药害,甚至造成死亡.在熏蒸剂量和熏蒸时间一致时,随着真空度的提高,对试验花卉的药害逐步加重.  相似文献   

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