共查询到20条相似文献，搜索用时 671 毫秒
1.
Kevin N
T Norman 《Pest management science》2000,56(2):154-158
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
2.
Kevin N. T. Norman 《Pest management science》1991,33(1):23-34
An automated gas chromatographic headspace method capable of detecting halogenated compounds in cereals, nuts and seeds at levels down to μg kg?1 or less has been developed and evaluated. Commodities were analysed directly without extraction or clean-up and a simple calibration technique offers a rapid screening quantitative analytical method. Comparison of results obtained using an established solvent extraction method with those obtained using the method described showed good quantitative agreement. Minimum detectable quantities were lower using the headspace method for every fumigant residue/commodity studied. The recommended analytical conditions are suitable for examination of further commodities for the fumigant residues examined and for other volatile halocarbons. 相似文献
3.
A method is presented for estimating the persistence and concentration of residual free methyl bromide (MB) present in apples during the aeration period following fumigation. The method is based on determining the rate of decline in concentration of methyl bromide in the exhaust air stream during aeration. The rate was shown to follow two consecutive pseudo-first-order decay curves. The first component of the curve resulted primarily from removal of MB from the free air space in the chamber, and the second component resulted from the desorption of MB from the apples. Estimates of the concentration of MB residue in apples were obtained from the regression parameters for the second decay curve. The technique gave good estimates of the residue concentration over a wide range of fumigation conditions and ventilation rates, and may be useful for determining the duration of aeration period required to achieve a proposed residue tolerance of 0.2 mg kg ?1 methyl bromide. 相似文献
4.
Highest inorganic bromine residues (30 ppm) were found when soil was fumigated with liquid methyl bromide (MB) introduced
by conventional means into evaporating dishes. With preheated (vaporized) MB or injection of MB/chloropicrin (CP) mixtures,
bromide concentrations were reduced by 50%. They were uniform throughout the soil (0 to 60 cm) except after MB/CP injection,
when larger residues were found in the 30-60 cm layer. Leaching with 2000 mp3/ha (20 cm) of water always reduced bromide content to 7.5 and 10 ppm at the 0-30 and 30-60 cm depth, respectively. Organic
amendments to soils substantially increased bromide levels up to 118 ppm, most of which was found in the upper soil layers;
two teachings with 2000 mp3 /ha water were required to return the soils to their normal state.Sclerotium rolfsii andFusarium oxysporum f. sp.dianthi cultures buried in soil were eliminated from the upper 30 cm with MB applied either conventionally or preheated. At 50 cm,
500 kg/ha of the preheated gas was superior to 1000 kg/ha of the cold gas. All MB fumigations suppressed carnation flower
yields compared with CP alone but were superior to no treatment. After leaching, MB-fumigated soils yielded the highest number
of flowers. 相似文献
5.
Abraham Gamliel Avi Grinstein Marina Beniches Jaacov Katan Jerome Fritsch Patrick Ducom 《Pest management science》1998,53(2):141-148
The permeability of plastic films to the fumigant methyl bromide (MB) was measured by two different methods, in order to facilitate the selection of films which are impermeable to the gas. Polyethylene-based films are highly permeable to MB, as evidenced by both methods. In contrast, multilayer coextruded films which have a layer of barrier material such as polyamide (PA) or ethylene-vinyl alcohol copolymer (EVOH) were significantly less permeable to MB, as reflected by the parameters permeability rate, time to 90% concentration (TC90, by the diffusion method) and lag-time values (by the variable-volume method). A significant correlation was found between the permeability rate assessed by the diffusion method and that obtained with the variable-volume method. Permeability of all films increased with temperature as evidenced by all tested parameters. This increase was more pronounced with polyethylene films, the permeabilities of which increased five- to six-fold when the temperature was increased from 20°C to 60°C. The effect of temperature on barrier-film permeability was less significant. Permeability of films to MB was affected by additional factors such as additives, the length of the monomer side-chain, and the thickness and density of polyethylene films. © 1998 SCI 相似文献
6.
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
7.
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
8.
9.
BACKGROUND
Ethanedinitrile (EDN) is a fumigant being commercialized worldwide as an alternative phytosanitary treatment to methyl bromide (MB) for forest products. The penetration characteristics of MB and EDN were measured through the bark of wooden blocks (100 × 100 × 50 mm) cut from the upper (average bark thickness 5 ± 2 mm) and lower (average bark thickness 25 ± 5 mm) trunk of recently felled pine (Pinus radiata D.Don) trees. Doses of 48 g m−3 MB and 50 g m−3 EDN were applied to chambers at 10 and 20°C for 10 h.RESULTS
Penetration of MB was influenced by the interaction between fumigation time and temperature, with concentrations increasing at a higher rate at 20°C compared with at 10°C. After 10 h, an average concentration of 8.05 ± 0.89 g m−3 had penetrated the bark of log sections at 20°C, whereas 5.20 ± 0.89 g m−3 was measured at 10°C. By contrast, the factors examined in this study did not significantly impact the penetration of EDN. Concentration × time (CT) values for MB under the bark were 35.20 ± 2.30 g h m−3 at 10°C and 55.85 ± 9.58 g h m−3 at 20°C; whereas for EDN, CT values were 19.50 ± 6.80 g h m−3 at 10°C and 19.08 ± 4.10 g h m−3 at 20°C.CONCLUSION
MB can achieve a higher concentration under the bark of log sections during simulated fumigations, but all of the factors examined affected the ability of MB to penetrate the bark of wooden blocks. By comparison, the penetration of EDN through the bark is more consistent than MB under laboratory conditions. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. 相似文献10.
Garlic bulbs heavily infected withDitylenchus dipsaci were chemically treated to control the nematode. Treatment with ethoprop resulted in greatest reduction of nematodes early in the season; oxamyl provided good control; methomyl was ineffective. Treating the soil with aldicarb or phenamiphos was also effective. Later in the season, nematode populations increased with all treatments and crop damage was severe. In a soil heavily infested with this pathogen, nematode populations in the untreated plots were initially low but had increased rapidly 100 days after planting, resulting in total loss of plants by the end of the season. Excellent control was obtained by treating the soil with methyl bromide (MB) or solar heating with transparent polyethylene sheets prior to planting, although MB treatment caused severe stunting of the plants. Treatment with ethylene dibromide (EDB) controlled the pathogen initially, but later in the season the population level increased. The yields (kg/m2) were: untreated, 0; solar heating, 2.325; EDB, 0.813; and MB, 1.152. 相似文献
11.
BACKGROUND: The combination of 1,3‐dichloropropene (1,3‐D) and dazomet (DZ) offers a potential alternative to methyl bromide (MB) for soil disinfection. MB is scheduled to be withdrawn from routine use by 2015 in developing countries. Combination treatments of 1,3‐D + DZ were evaluated in a laboratory study and in two commercial cucumber fields. RESULTS: Laboratory studies found that nearly all of the tested combinations of 1,3‐D and DZ displayed positive synergistic activity on root‐knot nematodes (Meloidogyne spp.), two major soilborne fungi (Fusarium spp. and Phytophthora spp.) and the seeds of two major weed species (Digitaria sanguinalis and Abutilon theophrasti). Field trials revealed that the combination of 1,3‐D and DZ (at 10 + 25 g m?2) successfully suppressed Meloidogyne spp. root galling, sharply reduced Fusarium spp. and Phytophthora spp. and maintained high cucumber yields. The combination treatment of 1,3‐D + DZ was more effective than 1,3‐D or DZ alone and provided results similar to methyl bromide with respect to pest control, plant mortality, plant height, yield and income. All of the treatments were significantly better than the non‐treated control. CONCLUSION: The results indicate that the tested combination of 1,3‐D and DZ offers an efficient alternative to methyl bromide for cucumber production. Copyright © 2012 Society of Chemical Industry 相似文献
12.
生物柴油作为精喹禾灵乳油中二甲苯替代溶剂的应用初探 总被引：5，自引：0，他引：5
为评价不同来源生物柴油作为溶剂配制精喹禾灵乳油的效果,采用气相色谱法测定了几种生物柴油中脂肪酸甲酯的种类及含量,利用相应制备的5%精喹禾灵乳油进行了防治禾本科杂草的盆栽试验,同时比较了不同生物柴油对药剂稀释液表面张力、干燥时间和在叶片表面沉积量等药液物理性状的影响。结果表明,用不同脂肪酸甲酯含量的生物柴油均能够制备出合格的5%精喹禾灵乳油,并且利用生物柴油制备的乳油在使用剂量为有效成分2 g/hm2时防效略高于常规以二甲苯为溶剂配制的乳油, 5 g/hm2和20 g/hm2剂量下无显著差异;生物柴油配制乳油稀释液与二甲苯配制乳油稀释液的表面张力差异不显著,但前者的沉积量则明显提高50%左右,能提高稀释液在小麦叶片的渗透速率。上述结果初步表明,生物柴油作为精喹禾灵乳油的替代溶剂具有一定的可行性。 相似文献
13.
Rupak Paul Rajvir Sharma Gita Kulshrestha Shashi Bala Singh 《Pest management science》2009,65(9):963-968
BACKGROUND: Metsulfuron‐methyl is a low‐application‐rate sulfonylurea herbicide that is widely used to control broad‐leaved weeds in wheat. Owing to its persistent nature, its residues may be present at phytotoxic levels for the next crop in rotation. Therefore, a comparative evaluation of HPLC and bioassay techniques was made for the analysis of this herbicide in wheat field soil. RESULTS: Metsulfuron‐methyl was applied to wheat crop at different rates (4, 8 and 12 AI ha?1) at 28 days after sowing as a post‐emergence application, and the soil was analysed for metsulfuron‐methyl residues by HPLC and lentil seed bioassay techniques. The bioassay was found to be the more sensitive technique. At the recommended rate of application, 4 g AI ha?1, the bioassay technique could detect the residue up to 30 days in surface soil, while, with HPLC, residues were not detectable on the 15th day. The half‐lives of metsulfuron‐methyl by HPLC and bioassay were calculated as 6.3–7.8 and 17.5 days respectively. Under field conditions, residues of metsulfuron‐methyl were also detected in subsurface soil by the bioassay technique at trace levels, but were not detected by the solvent extraction/HPLC method. CONCLUSION: Lentil seed bioassay is a more sensitive technique than HPLC. Traces of residues detected in subsurface soil indicated the mobility of metsulfuron‐methyl into lower layers. Copyright © 2009 Society of Chemical Industry 相似文献
14.
顶空气相色谱法测定土壤中氯化苦残留 总被引：2，自引：1，他引：1
建立了一种快速测定土壤中氯化苦残留的方法。用石油醚室温下浸提土壤30 min后漩涡振荡,离心后取上清液直接采用顶空气相色谱法测定。结果显示,在质量浓度0.005 ~4 mg/L范围内,线性相关系数R2=0.999。氯化苦的添加水平在0.012 5 ~1.25 mg/kg范围内,5次重复的平均添加回收率在82.7% ~109.9%之间,相对标准偏差(RSD)在8.4% ~9.5%之间,检测限为0.008 8 mg/kg,定量限为0.029 mg/kg 。该方法可以满足土壤中氯化苦残留测定的要求。 相似文献
15.
顶空气相色谱法测定小麦中熏蒸剂氰及其代谢物氰化氢的残留量 总被引：2，自引：1，他引：1
采用溶剂顶空毛细管气相色谱-氮磷检测器(NPD)建立了熏蒸剂氰(C2N2)及其代谢物氰化氢(HCN)在小麦中残留的分析方法。在气相与液相体积比(β)为4时,采用GS-Q大孔毛细管色谱柱和进样60 μL顶空气体,可提高C2N2和HCN的分离效果和灵敏度。以质量分数为50%的磷酸作溶剂,在25 ℃下平衡4 h,C2N2和HCN在液相与气相间的分配系数(k)分别为0.44和48.82。平衡温度和基质对C2N2和HCN挥发的影响存在差异,而盐化效应的影响较小。用50% 的磷酸提取熏蒸过的小麦72 h,释放至顶空的C2N2和HCN的量最大,用添加标准品的小麦作标准可评价熏蒸小麦中C2N2和HCN的残留量。C2N2和HCN标准曲线的线性范围分别在质量浓度为1.0~500 μg/L和1.2~500 μg/L之间,相关系数(R2)分别为0.999 7和0.999 8,相对标准偏差分别为4.6%和7.4%,检出限(LOD)分别为0.032和0.145 mg/kg,定量限(LOQ)分别为0.107和0.483 mg/kg。方法操作简单、灵敏度高、干扰少,适用于小麦中C2N2和HCN残留量的检测。 相似文献
16.
溴甲烷在草莓田的替代及减少其散发的技术 总被引：1，自引：1，他引：1
溴甲烷是一种消耗臭氧层的物质，根据《蒙特利尔议定书哥本哈根修正案》，发展中国家将于2015年淘汰。在我国溴甲烷消费量最大的地区，河北省满城县实施了中-意“溴甲烷土壤消毒替代技术及能力建设项目”。试验结果表明：威百亩和威百亩＋VIF，采用化学灌溉技术施药，是有前景的溴甲烷替代品，2001～2002年威百亩和威百亩＋VIF处理“达赛莱克特”品种的产量分别为26816kg／hm^2和23672kg／hm^2，而溴甲烷处理的产量为28346kg／hm^2；威百亩和威百亩＋VIF处理“理念”品种的产量分别为19844kg／hm^2和15989kg／hm^2而溴甲烷处理的产量为19657kg／hm^2；2002～2003年威百亩和威百亩＋VIF处理“达赛莱克特”品种的产量分别为23073kg／hm^223446kg／hm^2而溴甲烷处理的产量为25285kg／hm^2威百亩和威百亩＋VIF处理“全明星”品种的产量分别为：29594kg／hm^227677kg／hm^2而溴甲烷处理的产量为32191kg／hm^2产量结果经统计分析表明，威百亩、威百亩＋VIF与溴甲烷均无显著差异。溴甲烷＋VIF采用热法施药，其产量与溴甲烷无明显差异，但溴甲烷＋VIF能减少溴甲烷25％的用药量。太阳能消毒＋生物防治制剂的产量高于空白对照，有一定的防病增产效果，但显著低于溴甲烷处理的产量，不能作为溴甲烷的替代品。进口品种“理念”和当地主栽品种“全明星”对土传病害的抗性较差，在长势、产量方面均显著差于新引进品种“达赛莱克特”。虽然“达赛莱克特”对土传病害有一定的抗性，但与溴甲烷和威百亩处理区比较，空白对照区的产量仍显著低于药剂处理区的产量。 相似文献
17.
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
18.
Stephen T. Hadfield Jill K. Sadler Elek Bolygo Ian R. Hill 《Pest management science》1992,34(3):207-213
This paper describes the development of methods suitable for the sampling and analysis of the pyrethroid insecticides lambda-cyhalothrin and cypermethrin in natural waters. A solid-phase water-sampling method which avoids the requirement for transport and storage of large volumes of water is described. This method is shown to be capable of extracting trace levels (ng litre?-1) of the title compounds from natural waters with efficiencies of at least 80%. Chromatographic analysis of processed samples by gas chromatography–electron capture detection enables determination of residues at levels of 1–2 ng litre?-1 in water. 相似文献
19.
B. P. J. de Lacy Costello P. Evans R. J. Ewen H. E. Gunson P. R. H. Jones N. M. Ratcliffe † P. T. N. Spencer-Phillips 《Plant pathology》2001,50(4):489-496
Volatile organic compounds (VOCs) collected from potato tubers inoculated with Phytophthora infestans (late blight), Fusarium coeruleum (dry rot) or sterilized distilled water (as a control) were analysed using gas chromatography–mass spectrometry (GC–MS) and gas chromatography–flame ionization detection (GC–FID). A total of 52 volatiles were identified by GC–MS in the headspaces above P. infestans- and F. coeruleum- inoculated tubers after incubation for 42 days in the dark at 10°C. Of these VOCs, the six most abundant were common to both pathogens. These were benzothiazole (highest abundance), 2-ethyl-1-hexanol (second highest abundance), and at approximately equal third abundance, hexanal, 2-methylpropanoic acid-2,2-dimethyl-1-(2-hydroxy-1-methylethyl)-propyl ester, 2-methylpropanoic acid-3-hydroxy-2,4,4-trimethyl-pentyl ester and phenol. In addition, styrene also occurred at approximately equal third abundance in the headspace of F. coeruleum- inoculated tubers, but at lower abundance in the headspace of P. infestans- inoculated tubers. Some VOCs were specific to each pathogen. Butanal, 3-methylbutanal, undecane and verbenone were found at low levels only in the headspace of tubers inoculated with P. infestans , while 2-pentylfuran and copaene were found only in the headspace of tubers inoculated with F. coeruleum . Additionally GC–FID analysis identified ethanol and 2-propanol in the liquid exudate from both P. infestans - and F. coeruleum -inoculated tubers after incubation for 35 days, and in the headspace after incubation for 42 days. These data provide key information for developing a sensor-based early warning system for the detection of postharvest diseases in stored potato tubers. 相似文献
20.
Experiments were carried out to investigate the influence of different modified atmospheres, low pressures alone, methyl bromide
(MB) alone, and MB in combination with CO2 or low pressure, in causing nitidulid beetles to emigrate from infested dried fruit for which dates served as a model. All
the treatments at 4 h and 16 h exposure and at 26°C, had a marked influence in causing insects to abandon the infested fruit.
The most effective treatments at the two exposures were pressures of 50 mm Hg, and 1.4% O2 in air, both of which caused over 87% of the initial insect populations to emigrate from the fruit. At 4 h exposure, 2.8%
O2 was less effective than 100 mm Hg or MB. At 16 h exposure, MB+CO2 was third in effectiveness and 100 mm Hg was one of the least effective treatments. 相似文献