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1.
Procedures are described for the analysis of crops for residues of tetrachlorvinphos (Gardona, trans-isomer of dimethyl 1-(2′,4′,5′-trichlorophenyl)-2-chloroyinyl phosphate) insecticide together with methods for the analysis for residues of its isomer and its conjugated and non-conjugated breakdown products. Suitable procedures for the extraction are described together with procedures for the cleanup of the extracts by partition or column chromatography and final analysis down to 0·01 ppm or less by gas-liquid chromatography with electron capture detection. 相似文献
2.
Two procedures are described for the determination of residues of triadimenol and compared on cereal material. After extraction, purification is carried out by Florisil column chromatography in method I and by semi-preparative High-Performance Liquid Chromatography in method II. Triadimenol residues are quantified by gas chromatography with a thermoionic detector. With method I, interference was observed but not with method II. This specific procedure has been tested on other plant materials. Recoveries in the range of 90–98% indicate that this procedure is suitable for residue analysis of this fungicide with detection limits of 0·008 mg kg?1 in wheat grains, 0·03 mg kg?1 in wheat straw and 0·004–0·008 mg kg?1 in other plants. Maximum residue limits in France are: 0·1 mg kg?1 in grain, 2·0 mg kg?1 in straw and 1·0 mg kg?1 in other vegetables and fruit. 相似文献
3.
Nematicidal activity of the leaf powder, leaf extracts and formulated leaf extracts of Myrtus communis, an evergreen shrub that is widely distributed in Israel and other Mediterranean countries, was evaluated using the root‐knot nematode Meloidogyne javanica in in vitro and pot experiments. Leaf powder added to sand at 0·1% (w/w) reduced the number of juveniles recovered from the sand by more than 50%. Reduction in galling index and number of nematode eggs on tomato roots was also observed by incorporating the leaf powder at 0·1–0·4% (w/w) in the soil in pot experiments. Leaf powder extracts with methanol or ethanol showed the highest nematicidal activity among all extracts tested. Emulsifiable concentrates of leaf‐paste extract at a concentration as low as 0·005% (a.i., w/w) reduced the number of juveniles recovered from treated sand and the gall index of cucumber seedlings. The extract paste at 26 g m?2 was also effective in reducing the gall index of tomato plants in field‐plot experiments. The leaf powder at 0·2% and the formulated leaf‐paste extract at 0·02% were also nematicidal to Tylenchulus semipenetrans and Ditylenchus dipsaci, but not to Pratylenchus penetrans or Steinernema feltiae. At least three nematicidal compounds were found in the leaf extract upon fractionation by thin‐layer chromatography. The results suggest that the leaf powder and paste extract of M. communis are potential nematicides against root‐knot nematodes. 相似文献
4.
In an extensive field study conducted over five counties in southern Eire during the winter of 1988–89, 19 Barn Owl (Tyto alba) roosts and/or nests were located. The local farmers and landowners within about a one-mile radius of the Barn Owl sites were surveyed concerning their use of rodenticides and observations of any secondary rodenticide toxicity effects. Regurgitated owl pellets were collected: (a) for dissection and prey analysis, and (b) for chemical analysis to determine residues of the second-generation rodenticides, brodifacoum, difenacoum and flocoumafen. Most farmers interviewed used rodenticide baits (73%), and almost all (92%) stated that they took precautions to protect domestic and wild non-target animals. The four rodent species, brown rat, wood mouse, house mouse and bank vole provided 83% of the Barn Owl diet, and birds contributed another 12%. At least 97% of the 89 pellets analysed contained less than the limit of determination of the three second-generation rodenticides, 0·01–0·02 mg kg−1 of each isomer. Apparent residues in the remainder were likely to be the result of interference from co-extracted material. These results indicated that during the monitoring period, none of the owls studied was exposed to significant residues of these rodenticides in their prey. 相似文献
5.
A field study was conducted to investigate the persistence of tebufenozide in white spruce foliage. An aqueous suspension concentrate formulation, RH-5992 2F, was sprayed over single trees at three dosage rates, 35, 70 and 140 g of the active ingredient (AI), in 2·0 litre ha−1, using ground application equipment. Foliage was collected at different intervals of time up to 64 days after treatment and tebufenozide residues were measured by high-performance liquid chromatography. Foliage was also fed to laboratory-reared 4th- and 6th-instar spruce budworm (Choristoneura fumiferana Clemens). The data indicated that tebufenozide residues in foliage declined with time according to first-order kinetics. The average rate-constant and half-life of disappearance (DT50) were 0·0340 and 20·45 days, respectively. Larval mortality declined gradually, corresponding to the residues, but was still appreciable (49 to 70%) when the larvae were fed with foliage collected 64 days after treatment. The amount of foliage consumed by the larvae decreased when foliar residues of tebufenozide increased, thus indicating anti-feedant activity of the chemical. The LD50 values for both instars were similar and averagedc.25 ng per insect, but the LD90 values were significantly lower for 4th-instar than for 6th-instar, at 63·6 and 96·1 ng per insect respectively. This implies that, theoretically, at a foliar concentration of 1·0 μg tebufenozide g−1 foliage (fresh wt), the spruce budworm larva needs to consume 65 to 100 mg of foliage in 10 days to cause mortality in about 90% of a population of the insect. 相似文献
6.
The mobility and retention of atrazine and dicamba in six Atlantic Coastal Plain soils were estimated by soil thin-layer chromatography (soil-TLC). The soils studied were representative of the major agricultural regions in Delaware and were sampled, by horizon, to the water table. Four horizons from each profile were leached simultaneously with distilled water on one soil-TLC plate. Two values were obtained from each plate: the ratio of the distance traveled by the herbicide center of mass over that traveled by the solvent front (Rm), and a sorption distribution coefficient (Kd). The Rm values ranged from 0·06 to 0·94 for atrazine and from 0·80 to 0·94 for dicamba. Herbicide mobility was found to be greatest in coarse-textured soil horizons that contained low levels of organic matter, clay, and Fe and Al oxides. Correlation analysis indicated that effective cation exchange capacity, exchangeable acidity, exchangeable aluminum, and clay were useful predictive variables or both atrazine mobility and sorption. Organic matter was not useful for predicting soil-TLC derived sorption estimates; however, it was correlated to Kd-batch estimates. Distribution coefficients calculated from soil-TLC data were found to be in general agreement with Kd values obtained for the same soils by batch equilibrium techniques. The average Kd-soil-TLC values for atrazine and dicamba were 2·09(±2·24) and 0·03(±0·02), respectively. The ratio of the batch Kd to the soil-TLC Kd ranged from 0·1 to 19 (x̄=1·6, SD=3·8) for atrazine and from 2·9 to 38 (x̄=12·6, SD=8·7) for dicamba. Thus, although for some horizons agreement between the two methods was good, for other horizons significant discrepancies existed. It is suggested that the soil-TLC gives results under non-equilibrium conditions, whereas the batch procedure is, by definition, at quasi-equilibrium. These fundamental differences may account for the observed differences between the two methods. It is also suggested that, due to this difference, the soil-TLC procedure can provide additional information relevant to herbicide partitioning in the field environment that is not provided by traditional batch equilibrium techniques. © 1998 Society of Chemical Industry 相似文献
7.
Harry J. Strek 《Pest management science》1998,53(1):29-51
The behaviour and fate of chlorsulfuron in aqueous and soil systems were examined in laboratory studies. Aqueous hydrolysis was pH-dependent and followed pseudo-first-order degradation kinetics at 25°C, with faster hydrolysis occurring at pH 5 (half-life 24 days) than at either pH 7 or 9 (half-lives >365 days). Degradation occurred primarily by cleavage of the sulfonylurea bridge to form the major metabolites chlorobenzenesulfonamide (2-chlorobenzenesulfonamide) and triazine amine (4-methoxy-6-methyl-1,3,5-triazin-2-amine). This route is a major degradation pathway in water and soil systems. Aqueous photolysis (corrected for hydrolysis) proceeded much more slowly (half-life 198 days) than aqueous hydrolysis and is not expected to contribute significantly to overall degradation. Hydrolysis in soil thin-layer plates exposed to light (half-life 80 days), however, progressed at a much faster rate than in dark controls (half life 130 days), which suggests that a mechanism other than direct photolysis may have been operative. An aerobic soil metabolism study (25°C) in a Keyport silt loam soil (pH 6·4, 2·8% OM) showed that degradation was rapid (half-life 20 days). Dissipation in an anaerobic sediment/water system (initial pH of water phase 6·7, final pH 7·4) progressed much more slowly (half-life >365 days) than in aerobic soil systems. Major degradation products in aerobic soil included the chlorobenzenesulfonamide and triazine amine as in the aqueous hydrolysis study. Neither of these degradation products exhibited phytotoxicity to a variety of crop and weed species in a glasshouse experiment, and both exhibited an acute toxicological profile similar to that of chlorsulfuron in a battery of standard tests. Demethylation of the 4-methoxy group on the triazine moiety and subsequent cleavage of the triazine ring is another pathway found in both aqueous solution and soils, though different bonds on the triazine amine appear to be cleaved in the two systems. Hydroxylation of the benzenesulfonamide moiety is a minor degradation pathway found in soils. Two soils amended with 0·1 and 1·0 mg kg-1 chlorsulfuron showed slight stimulation of nitrification. The 1·0 mg kg-1 concentration of chlorsulfuron resulted in minor stimulation and inhibition of 14C-cellulose and 14C-protein degradation, respectively, in the same soils. Batch equilibrium adsorption studies conducted on four soils showed that adsorption was low in this system (Koc 13–54). Soil thin-layer chromatography of chlorsulfuron (Rf=0·55–0·86) and its major degradation products demonstrated that the chlorobenzenesulfonamide (Rf=0·34–0·68) had slightly less mobility and that the triazine amine (Rf=0·035–0·40) was much less mobile than chlorsulfuron. In an aged column leaching study, subsamples of a Fallsington sandy loam (pHwater 5·6, OM 1·4%) or a Flanagan silt loam (pHwater 6·4, OM 4·0%) were treated with chlorsulfuron, aged moist for 30 days in a glasshouse and then placed upon a prewet column of the same soil type prior to initiation of leaching. This treatment resulted in the retention of much more total radioactivity (including degradation products) than by a prewet column, where initiation of leaching began immediately after chlorsulfuron application, without aging (primarily chlorsulfuron parent). © 1998 SCI 相似文献
8.
The colorimetric method for the analysis of the molluscicide trifenmorph (N-tritylmorpholine) in water has been extended to allow analysis of trifenmorph alone under field conditions. A simple chromatographic stage has been used to reject the hydrolysis product triphenylmethanol. The modified procedure has been useful in the field during recent applications of trifenmorph. 相似文献
9.
Paolo Maini 《Pest management science》1992,34(1):45-52
In order to obtain residue data from the application of the algicide endothal in Italian rice paddy fields, two experiments were carried out using a 50 g kg?1 granular formulation in a small pond and the same granular and two liquid formulations in actual paddy fields of the Italian rice growing area. Endothal decay in the pond water was very rapid, reaching residue levels of 0·01-1·02 mg litre?1 in two days and 0·004-0·01 mg litre?1 at the third day. The muddy soil of the pond was free from measurable endothal residues( <0·02 mg kg?1). In the paddy-field waters, the endothal decay was slower, with an average half-life time of 3·3 days, independently of the type of formulation. The actual residues in water after 6 days ranged from 0·3 to 1·3 mg litre?1 according to the initial amount of product applied, and, consequently, to the initial concentration in water. Rice samples collected at the normal harvest time from the two paddy fields, treated with three different formulations, showed no endothal residue at the minimum detectable level of 0·01 mg kg?1. 相似文献
10.
A wide range of crops including top fruit, cereals, brassicas, root vegetables and cotton from field trials in several countries in 1965, 1966, 1967 and 1968 have been analysed for residues of tetrachlorvinphos (Gardona, trans-homer of dimethyl 1-(2′,4′,5′-trichlorophenyl)-2-chlorovinyl phosphate) foliar insecticide, its isomer and its potential breakdown products. The residues under field conditions were mainly of tetrachlorvinphos, its isomer and 1-(2′,4′,5′-trichlorophenyl)ethan-1-ol in free and sugar-conjugated forms. Tetrachlorvinphos was not unduly persistent on the crops and its initial half-life varied from 2 days on cabbage, to 7 days on potato foliage and to 12 days on pears (after the last of five applications). From one week after the final application onwards the highest residues of tetrachlorvinphos observed were on olives (1 ppm after 18 days after a single application of 0·1 % active material), maize leaf (2·8 ppm at 9·5 weeks after the last of two applications at 3 kg/ha), and cabbage (1·9 ppm at 12 days after the last of three applications at 0·5 kg/ha). The maximum residues of the alcohol in the free form were 3·2 ppm on maize leaf at 8 weeks from the second application at 1·5 kg/ha and in the conjugated form were 1·0 ppm on cauliflowers at 6 days after the last of four applications at 0·5 kg/ha. 相似文献
11.
Charles V. Eadsforth Alan J. Dutton Elizabeth G. Harrison John A. Vaughan 《Pest management science》1991,32(1):105-119
A study was carried out to assess the feasibility of monitoring the exposure of barn owls (Tyto alba) to an anticoagulant rodenticide, flocoumafen, by analysis of residues in regurgitated pellets following consumption of flocoumafen-contaminated mice. Mice were fed on a diet containing [14C]flocoumafen, equivalent to 12 mg kg?1, and killed 24 h later. A single [14C]flocoumafen-contaminated mouse was fed to each of four captive barn owls, equivalent to 0·11-0·23 mg kg?1 per bird, followed on seven successive days by control diet (i.e. undosed mice). The [14C]flocoumafen dose was eliminated by the owls over the eight-day period in pellets (44%, range 35–55%) and faeces (18%, range 11–21%), with the highest residues being observed in samples from the first 24-h period. Further detailed analysis of the pellets confirmed that flocoumafen residues in the first-day pellets represented 15% (range 8–26%) of the original flocoumafen residues ingested by the barn owls. Calculations based on these data and typical flocoumafen residues in live captured rodents (following baiting) confirm that pellet residue analysis is a sensitive and appropriate method for the non-invasive monitoring of exposure of barn owls to flocoumafen. There were no symptoms of anticoagulant poisoning in any of the birds; two of the birds were successfully paired the next season and produced fledgelings. 相似文献
12.
The performance of a newly developed column method for pesticide transformation rate measurements in the subsoil was tested using (Z)- and (E)-3-chloroallyl alcohol as model compounds. Sandy anaerobic water-saturated subsoil was collected at between 1·8 and 2·3 m below the surface of a flower-bulb field. Transformation rates were measured using subsoil columns that were filled in situ and were compared with the transformation rates in laboratory incubation systems. In the column experiment the half-life ranged from 0·5 to 5·2 days for (Z)-3-chloroallyl alcohol and from 1·0 to 5·5 days for (E)-3-chloroallyl alcohol. The capacity of the saturated subsoil for transformation of both isomers increased in the course of the column experiment. In the incubation experiment the 3-chloroallyl alcohols were transformed gradually in the first three days, with a half-life of 1·9 days for both isomers. Thereafter the transformation rate accelerated. The general conclusion is that the column method yields results similar to those of the incubation method for these rapidly transforming compounds. 相似文献
13.
An RP-HPLC method for the quantitative determination of chlorotoluron in technical products and formulations has been developed, using as column μBondapak C18, 250×4·6 (ID) mm, as eluent methanol+water+acetic acid (60+40+0·1 by volume), with detection by UV at 243 nm. Recoveries were 99·3–100%, RSD (n=5)<0·47%. © of SCI. 相似文献
14.
气相色谱-质谱法测定烟叶和土壤中丁硫克百威及其代谢产物的残留 总被引：2，自引：0，他引：2
建立了气相色谱-质谱法同时检测烟叶和土壤中丁硫克百威及其代谢产物(克百威和3-羟基克百威)残留量的分析方法。土壤样品用丙酮-石油醚[V(丙酮)∶V(石油醚)=1∶4]混合溶液提取,无需净化;鲜烟叶样品用丙酮-乙腈[V(丙酮)∶V(乙腈)=1∶9]混合溶液提取;烤后烟叶用乙腈提取。鲜烟叶和烤后烟叶提取液经旋转蒸发浓缩后,用弗罗里硅土柱净化。结果表明:在0.05~1 mg/kg添加水平下,丁硫克百威及其代谢产物的平均回收率在74%~99%之间,相对标准偏差(RSD,n=5)在1.5%~9.2%之间。该方法的前处理相对于萃取过程较简单,其准确度、精密度和灵敏度均符合农药残留分析与检测的技术要求,适合于丁硫克百威及其代谢产物在烟叶和土壤中的残留分析与检测。 相似文献
15.
The present study reports on the insecticidal and acaricidal potentials of dibenzyltrisulfide (DBTS) isolated from the roots of Petiveria alliacea L. using thin layer and high performance liquid chromatography. The 96-h LD50 value (μg per tick) obtained for adult Boophilus microplus (Canestrini) topically treated with DBTS was 0·920. The LD50 values obtained for three commercial acaricides dimethoate, lindane and carbaryl were 4·6, 9·3 and 6·9 μg per tick respectively. The IOD50 and IHD50 (concentrations inhibiting egg laying and hatching by 50% respectively) in μg per tick doses for DBTS were 0·22 and 0·24 respectively. The 24-h LD50 dose (μg per insect) obtained for DBTS on adult Cylas formicarius elegantulus (Summer) was 0·193 μg per insect. The vapour from a stock solution of 5 g litre-1 of DBTS was highly toxic to adult Hypothenemus hampei Ferr. inside coffee berries, inflicting 89% mortality within 24 h. © 1997 SCI. 相似文献
16.
Michael Londershausen Andreas Turberg Barbara Bieseler Marco Lennartz Martin G. Peter 《Pest management science》1996,48(4):305-314
The molecular weight pattern and the stage-specific activities of chitinases from the blowfly Lucilia cuprina, the tick Boophilus microplus and the intestinal nematode Haemonchus contortus were examined. Chitinolytic enzymes could be detected in all parasite species tested, but the activity was different between the stages. Highest chitinolytic titers were found in blowfly pupae (83 kDa, 118 kDa), hatching larvae of ticks (58 kDa, 94 kDa) and nematode eggs (43 kDa). Leaves from ethylene-treated bean plants Phaseolus vulgaris expressed two basic Class I chitinases (Ia, Ib) of 34 kDa, differing in their amino acid sequences at residue 33 and 34 (Ia: glycine, proline; Ib: lysine, aspartic acid). Inhibitor studies with blowfly pupae revealed that allosamidin (IC50=0·32 (±0·02) μM ) was by far the best inhibitor when compared with various amino sugar derivatives. This compound also inhibited chitinases from tick larvae (IC50=0·69(±0·10) μM ) and nematode eggs (IC50=0·048(±0·0045) μM ) specifically. Whereas Class Ia chitinase from bean leaves was inhibited only up to 18% by 10 μM allosamidin, it had an IC50 of 1(±0·14) μM for the Ib type, which is the first plant chitinase described to be highly sensitive to allosamidin. 相似文献
17.
高效液相色谱法测定小麦和土壤中炔草酯及其代谢物炔草酸的残留量 总被引：3，自引：1，他引：2
建立了应用高效液相色谱分别测定炔草酯及其代谢物炔草酸在小麦和土壤中残留量的方法。样品经乙酸乙酯或丙酮提取,中性氧化铝柱层析净化,高效液相色谱法测定。结果表明:炔草酯在小麦籽粒、植株和土壤中的平均回收率为80.4%~92.5%,相对标准偏差(RSD)为1.5%~4.4%;炔草酸的平均回收率为71.7%~83.8%,RSD为2.3%~6.0%;炔草酯和炔草酸的最小检出量分别为1.0×10-9和2.0×10-10 g;在籽粒、植株和土壤中炔草酯和炔草酸的最低检测浓度分别为0.02、0.05、0.02 mg/kg和0.01、0.02、0.01 mg/kg。 相似文献
18.
Allan J. Cessna 《Pest management science》1992,36(1):31-33
The dissipation of mecoprop in wheat (Triticum aestivum L.) and oat (Avena sativa L.) was monitored over a growing season following post-emergence application of the dimethylamine salt of mecoprop to each crop at 1·1 kg ha?1. Residues of mecoprop, as its methyl ester, were determined gas chromatographically using electrolytic conductivity detection. Initial residues in wheat (119 (±20) mg kg?1) and oat (95·3 (± 10·0) mg kg?1) on the day of application (four-leaf stage of wheat and four- to five-leaf stage of oat) decreased to 0·1 to 0·2 mg kg?1, respectively, within six weeks. Residues were non-detectable in the mature seed of both crops. Recoveries of mecoprop were in the order of 90% from the green tissue and seed of both crops fortified at 0·05 mg kg?1. 相似文献
19.
This study investigated the influence of UV‐B radiation (280–320 nm) on survival of Candida oleophila strain O, an antagonist yeast that prevents postharvest diseases caused by Botrytis cinerea and Penicillium expansum on apple and pear fruits. Lethal doses (LD50 and LD90) were, respectively, 0·89 and 1·45 Kj m?2 for in vitro exposure and 3·06 and 5·5 Kj m?2 for in vivo exposure. A screening test of UV‐B protectants for strain O was also evaluated under in vitro and in vivo conditions. The in vitro results showed that sodium ascorbate (0·1% and 0·01%), riboflavin (0·1%) and uric acid (0·1% and 0·01%) were the most effective and most suitable protectants. However, only riboflavin (0·1%) and uric acid (0·1%) were effective under in vivo conditions. The efficacy obtained with strain O against P. expansum, when subjected to UV‐B radiation, was 75·0% and 49·2% for pathogen concentrations of 105 and 106 spores mL?1, respectively. Adding riboflavin to strain O gave a similar efficacy (64·2%). Applying strain O together with uric acid (0·1%) was less active (47·7%). Nonetheless, its efficacy when applied with the antioxidants sodium ascorbate (71·1%) or ascorbic acid (82·5%) was the greatest. Riboflavin and uric acid were the most cost‐effective protectants, and could be included in the final formulation of strain O when applied preharvest. 相似文献
20.
Angeles Adn Pedro Del Estal Flor Budia Manuel Gonzlez Elisa Viuela 《Pest management science》1996,48(3):261-268
Laboratory studies were conducted to determine the effect of the naturally derived compound spinosad on Ceratitis capitata Wied. (Diptera, Tephritidae). The organophosphate fenthion was used as a standard. Direct dose-dependent mortality and reduced fecundity were observed in oral treatment of adults with spinosad. The LC90 values 14 h and seven days after treatment were 19·50 and 0·49 mg litre−1 respectively. Fenthion was less active (the LC50 eight days after treatment was 1·17 mg litre−1) and did not affect the fecundity of the fly. Adults were also very susceptible to spinosad and fenthion via residual contact. For spinosad, 100% mortality was recorded 48 h after treatment for a dose of 10 mg litre−1. Spinosad was more effective than fenthion in suppressing larval development when neonate larvae were reared on treated diet supplemented with a range of concentrations from 0·02 to 0·83 mg kg−1 diet. Last-instar larvae were much less susceptible to spinosad or fenthion when exposed via dipping or when they pupated in treated medium and both products had similar performance. A lack of ovicidal activity was observed in direct egg-treatments with spinosad but significant reductions from 1 mg litre−1 onwards were recorded for fenthion. 相似文献