Evaluation of inexpensive thin-layer chromatographic procedures for the estimation of some organophosphorus and carbamate insecticide residues in fruit and vegetables

Modified versions of previously published procedures for the extraction and clean-up of some organophosphorus insecticide residues in fruits and vegetables are described, and their usefulness in combination with selected thin-layer chromatographic procedures is experimentally assessed for several pesticides in apples, oranges, tomatoes, carrots and peas. A simple extraction procedure for insecticidal carbamates is similarly evaluated for carbaryl and propoxur residues in apples, carrots and peas. Semi-quantitative estimation, by visual comparison with standards, is shown to be possible in many cases at residue levels as low as 0.4 mg kg^?1, and the combined procedures should be useful in the screening of fruits or vegetables for compliance with maximum residue limits.     

5种药剂对入侵新害虫扶桑绵粉蚧的防治效果

扶桑绵粉蚧作为一种新的入侵害虫,具有潜在危害性,国内尚无科学的防控技术,为了科学防控此害虫,选择5种常用药剂进行防治效果研究,结果表明:40%劲克介EC、40%氧化乐果EC和48%乐斯本EC都是比较理想防治药剂。     

Methods for visualizing hyaline fungi for the detection of antifungal compounds on thin-layer chromatograms

Two methods facilitating the use of hyaline fungi for the detection of antifungal compounds on thin-layer chromatograms are described. Fungal growth was visualized under ultraviolet light either by the metabolic release of fluorescein from the esterase substrate fluorescein diacetate, or by the binding of a fluorescent brightener (Calcofluor White M2R New, or Tinopal-CBS) to the mycelium on the TLC plate.
These methods were used to demonstrate compounds inhibitory to the wood-decay fungus Heterobasidion annosum in bark extracts of Sitka spruce ( Picea sitchensis ).     

Adsorption of systemic fungicides and a herbicide by some components of plant tissues,in relation to some physicochemical properties of the pesticides

Lignin, an important component of plant tissues, adsorbed five systemic fungicides and one herbicide (carbendazim, triadimefon, nuarimol, triarimol, fenarimol and fluometuron) more strongly than bovine serum albumin, cellulose, ethylcellulose or sodium polygalacturonate. Significant correlations were found between the extent of the adsorption of the pesticides on the lignins extracted from three different plant species, and the log Poet (Poet is the octan-1-ol/water partition coefficient) of the compounds. The more lipophilic fungicides triarimol and fenarimol (log Poet about 2.6) were adsorbed to the greatest extent. Fluometuron, triadimefon and nuarimol (log Poet about 2.0) were moderately adsorbed, whereas carbendazim with the lowest log Poet (1.34 at pH 5.0), was adsorbed more than expected from its Poet value. The anomaly of carbendazim is discussed; it is ascribed to it's partial protonation at pH 5.0, whereas the other pesticides were non-ionised.     

The effect of some pesticides on the larvae of Cirrospilus vittatus,a parasite of the apple leaf miner Stigmella malella,in a laboratory experiment

Samenvatting In laboratoriumproeven werd aangetoond dat een zeer groot gedeelte van de larven van de parasiet van de appelbladmineerder door een behandeling met parathion in de bladmijnen gedood wordt (Tabel 1). Met triamifos en captan werd ten opzichte van de behandelingen met water een iets hogere sterfte waargenomen; dit verschil was evenwel wiskundig niet betrouwbaar. In het najaar bleek de dodende werking van parathion met het verloop van de tijd enigszins af te nemen. De oorzaak hiervan moet gezocht worden in een invloed van de lagere temperatuur of in het in diapauze gaan van de larven.     

一种植物病毒检测新方法—纳米上转换荧光技术

随着大豆进口量的日益增加,大豆携带病毒传入我国的风险在不断增大,高效、快速地进行植物病毒检测,防止外来有害生物入侵,是目前各口岸植物检疫工作的重点。本文介绍了一种植物病毒检测的新方法—纳米上转换荧光技术。该技术是一种利用磁性纳米颗粒(magnetic nanoparticles, MNP)进行病毒分离、富集和定位;同时引入上转换荧光(up converting phosphor, UCP)材料作为标记物的免疫检测方法,具有高度的抗干扰性、多元性、稳定性和安全性等特点。     

High-performance liquid chromatographic method for the determination of carbendazim residues in crops,grains, and wines with fluorescent detection

A normal-phase high-performance liquid chromatographic method is described for the determination of carbendazim in wine, cereals and fruits. Residues are extracted from samples with methanol. Preliminary liquid partitioning into hexane may be necessary, according to the crops, followed by liquid partitioning from aqueous solution into dichloromethane. Purification is performed by silica-column chromatography or with a silica solid-phase extraction cartridge. Determination and quantification are made by HPLC using an aminobonded stationary phase with fluorescent detection at 285/315 nm. Recoveries range from 80 to 95% for various fortification levels. The method provides a minimum detectable amount below 0.1 ng and quantification limits for various samples are between 0.01 mg kg_-1 and 0.1 mg kg_-1.     

The effect of the annual use of some pesticides on soil microorganisms,pesticide residues in soil and carrot yields

The study deals with the effect of common, annually-used pesticides on soil microorganisms, pesticide residues in soil, and carrot (Daucus carota) yields in Central Finland. Linuron residues in carrot roots were also analysed. Thiram+lindane and dimethoate were applied from 1973–1981 at the commercially recommended doses on experimental plots of carrots, linuron was applied at twice the recommended rate from 1973–1979 and at the normal rate thereafter and in addition TCA was applied in 1978. Maleic hydrazide was used in the years 1973–1976, and glyphosate after 1977. The numbers of different soil microorganisms, their activities and the pesticide residues were studied from autumn 1978 to 1981. The pesticide treatments reduced the growth of soil algae but increased the total number of microorganisms and the number of aerobic spore-forming bacteria. Linuron residues in the soil were 0.9–2.8 mg kg^?1 in the growing season and 1.2–1.7 mg kg^?1 in the autumn, 3 months after application. The residues of glyphosate in the soil were 0.7 mg kg^?1 in the autumn, 41 days after the treatment, and had declined to a level of about 0.2 mg kg^?1 by the following summer. In the pesticide-treated plots the carrot yield was only 20–60% of the yield in the hand-weeded plots. The herbicide programme controlled most of the annual weeds but not couchgrass Elymus repens and milk sow-thistle Sonchus arvensis.     

A new selective medium for Burkholderia caryophylli, the causal agent of carnation bacterial wilt

A new selective medium (APCA medium) was developed for the isolation of Burkholderia caryophylli , the causal agent of carnation bacterial wilt, from both plants and soil. The optimal concentration and combination of antibiotics was investigated to determine the most selective condition for growing B .  caryophylli . The resultant composition of the medium per litre was: 0·79 g (NH₄)₂SO₄, 1·0 g KH₂PO₄, 0·5 g MgSO₄ · 7H₂O, 0·2 g KCl, 2·0 g D-arabinose, 5 mg crystal violet, 50 mg cycloheximide, 50 mg polymyxin B sulphate, 50 mg ampicillin sodium, 10 mg chloramphenicol, 25 mg blue tetrazolium, and 15 g agar. Plating efficiency ranged from 119 to 174% with an average of 141% compared to that of nutrient agar. The bacterium was successfully isolated from contaminated soil and plant tissues with this medium. Moreover, the medium almost completely inhibited the growth of other plant pathogenic bacteria and soil saprophytes. This selectivity was high enough to detect B . caryophylli in contaminated soil.     

植物病毒检测新技术研究进展

本文主要介绍了酶联免疫吸附测定、快速免疫滤纸测定、免疫胶体金技术、毛细管区带电泳、免疫PCR等血清学方法和PCR、分子信标、实时RT-PCR、核酸杂交等分子生物学方法的原理及特点,并重点介绍了近几年发展起来的免疫胶体金技术、毛细管区带电泳、分子信标和TaqMan实时RT-PCR等植物病毒检测技术.     

A new method for selective diagnostic staining of hooks of echinococci, cysticerci and tapeworms in histological sections

This paper describes a new method for selective staining of hooks of echinococci, cysticerci and tapeworms in histological sections. The method is based on pre-staining in hematoxylin, then the preparations are stained overnight in dilute polychrome blue and differentiated with tartrazine in Cellosolve (Ethylene glycol monoethyl ether or Ethylene glycol monomethyl ether). The hooks stain blue, nuclei brown to brown-green, and cell plasma is yellow. The hooks stain very brightly, which enables the identification of parasite remnants in granulomas and scars. The intensity of staining depends on the grade of maturity and sclerotization of hooks and these are readily observed, even in lower magnifications. The staining was successfully used in a variety of parasites.     

葡萄卷叶伴随病毒2实时荧光定量RT-PCR技术的检测应用

通过引物筛选和体系优化建立了葡萄卷叶伴随病毒2 Grapevine leafroll-associated virus 2(GLRaV-2)的SYBR GreenⅠ染料法实时荧光定量RT-PCR检测技术。该技术标准曲线扩增效率为102.2%,决定系数为0.999,最低检出限可达10^-3稀释梯度,是常规RT-PCR的100倍。对不同季节和不同部位葡萄样品的检出率普遍高于常规RT-PCR。春夏秋季样品检出率分别为67%、89%和86%,比常规RT-PCR检出率分别高42%、28%和17%。冬季休眠枝条检出率最高(100%),与常规RT-PCR相同。夏季老叶柄和卷须、秋季和冬季枝条等样品检测效果最好,检出率均为100%。对来自我国17个省38个品种的116份田间葡萄样品检测结果表明,qRT-PCR共检测到10个样品为阳性,检出率略高于常规RT-PCR。     

The antifeedant effect of some new withanolides on three insect species,spodoptera littoralis,epilachna varivestis andtribolium castaneum

The antifeedant effect of several new withanolides on larvae ofSpodoptera littoralis, Epilachna varivestis andTribolium castaneum was investigated. 2,3-Dihydrowithanolide E (II) was an antifeedant forS. littoralis andE. varivestis; nicalbin A (XIV), and a mixture of withanicandrin (IX) and daturalactone A (X), were active against E. varivestis andT. castaneum. Some activity was shown by 6β,14α,17β,20α_F-tetrahydroxy-1-oxowitha-2,4,24-trienolide (V) againstS. littoralis; 4β,5β-epoxy-6α,14α,17β,20α_F-tetrahydroxy-l-oxowitha-2,24-dienolide (VII) againstE. varivestis andT. castaneum; 5α,6α,-epoxy-14α,17β,20α_F-trihydroxy-1-oxowitha-2,24-dienolide (VI) againstE. varivestis; and nicalbin B (XV) againstT. castaneum.     

Chlorophyll fluorescence imaging: a new method for rapid detection of herbicide resistance in Alopecurus myosuroides

Due to the steadily increasing number of putative herbicide‐resistant weed populations, the demand for rapid in‐season tests is rising. In this study, we introduce a new quantitative herbicide‐resistance test system based on chlorophyll fluorescence imaging analysis of photosynthesis‐related parameters. Susceptible and herbicide‐resistant populations of Alopecurus myosuroides (black‐grass) were cultivated in multiwell tissue culture plates containing nutrient agar and different dosages of fenoxaprop‐P‐ethyl and mesosulfuron+iodosulfuron. The maximum quantum efficiency of the PSII was measured 3 h after transplanting (HAT) and then for seven days every 24 h. Data of maximum quantum efficiency of the PSII were compared with standard whole‐plant pot tests and molecular tests for target‐site mutations. It was possible to fit dose‐response curves and calculate corresponding resistance factors for ED90 for all populations tested using the chlorophyll fluorescence imaging. It was possible to distinguish between resistant and susceptible populations. The results of the chlorophyll fluorescence imaging corresponded well with the standard whole‐plant pot tests in the glasshouse. However, populations with proved target‐site mutations did not differ from other herbicide‐resistant populations in the maximum quantum efficiency values of the PSII. We conclude that the chlorophyll fluorescence imaging provides reliable data on herbicide resistance for both modes of action tested in a shorter time and using less space, compared with standard whole‐plant pot tests in the glasshouse.     

Effects of selected pesticides and adjuvants on germination and vegetative growth of Phomopsis amaranthicola, a biocontrol agent for Amaranthus spp.

Phomopsis amaranthicola, a bioherbicide agent for Amaranthus spp., was tested in vitro for its compatibility with commercial formulations of 16 adjuvants, 24 herbicides, nine fungicides and four insecticides at 2X, 1X (highest labelled product dose rate), 0.75X, 0.5X and 0.25X concentrations. These chemicals were tested for their effects on spore germination. Selected herbicides and fungicides at 1X were also tested for their influence on colony growth and sporulation. All tested compounds were finally categorized in compatibility classes regarding germination, mycelial growth and sporulation such as low, medium and high compatibility. High compatibility in terms of germination and fungal colony growth was only observed with the herbicide bentazone. Many of the adjuvants tested were highly compatible in the germination studies. Most fungicides and insecticides had medium and low compatibility with P. amaranthicola. Effects of pesticides on spore germination did not fully correspond with their effects on colony growth. Thus, it is possible to integrate the use of P. amaranthicola with some herbicides, fungicides, insecticides and adjuvants but not others. A case‐by‐case selection of application methods, such as tank‐mix or sequential application, along with proper timing of applications of the fungus and the chemical agents will be necessary.     

2-arylalkanoates,a new group of synthetic pyrethroid esters not containing cyclopropanecarboxylates

Although structure modifications of natural pyrethrin constituents have disclosed a variety of potent synthetic analogues, all known examples are cyclopropanecarboxylate esters, a grouping that appeared to be essential for insecticidal activity. Some new substituted 2-phenylalkanoates, whose biological activities are of a similar nature and potency to those of conventional pyrethroids, are now reported. 5-Benzyl-3-furylmethyl and 3-phenoxybenzyl 3-methyl-2-phenylbutyrates and their analogues are potent insecticides. Activity is increased on the introduction of appropriate groups into the 3 and/or 4-positions of the aryl ring and the (S)-2-phenylalkanoates are far more active than their (R)-enantiomorphs. Structure/activity relationships are compared with those for conventional pyrethroids. Some of the new series compare favourably with typical insecticides in tests against Musca domestica, Spodoptera litura and Plutella xylostella.     

两种柑橘新病毒双重RT-PCR检测体系的建立及应用

正柑橘黄化脉明病毒(Citrus yellow vein clearing virus,CYVCV)和柑橘褪绿矮化病毒(Citrus chlorotic dwarf-associated virus,CCDaV)是2种最近在我国发生的柑橘病毒(Chen et al.,2014;Guo et al.,2015),主要通过带病苗木和昆虫传播(陈洪明等,2015),对我国柑橘产业造成了严重损失。目前尚无防治CYVCV和CCDaV的药剂,种植无病毒苗木和加强病害检测是重要的防治途径。当前虽已建立了CYVCV和CCDaV的RT-PCR检测方法(Loconsole et al.,2012;陈洪明等,2015),但鉴于田间可能存在     

Host range and some properties of Physalis mosaic virus,a new virus of the turnip yellow mosaic virus group

An apparently undescribed virus was isolated fromPhysalis subglabrata in Illinois, USA, and its properties were studied. The virus was namedPhysalis mosaic virus (PMV). It was readily transmitted by sap inoculation to 23 out of 34 Solanaceae tested, toChenopodium foetidum andSonchus oleraceus but not to 28 other non-solanaceous species inoculated. Purified preparations of PMV contained isometric particles of 27 nm in diameter, which sedimented as two components with sedimentation coefficients of 50 and 112 S. The 112 S component was infectious, the 52 S component was not. The virus contained 38% ribonucleic acid with a molar base content of G 14.4%, A 22.9%, C 37,2% and U 25.5%.Purified preparations were highly infectious; a concentration of about 6000 particles per ml was infectious on plants.PMV is a member of the Andean potato latent virus subgroup of the turnip yellow mosaic virus group. The virus was closely related to the viruses: Andean potato latent, belladonna mottle, dulcamara mottle and egg-plant mosaic.Samenvatting Een nog niet eerder beschreven virus, dat in de staat Illinois (V.S. van Amerika) opPhysalis subglabrata was gevonden, werd in Wageningen bestudeerd. Het virus dat Physalis mosaic virus (PMV) (in het Nederlands:Physalis-mozaïekvirus) werd genoemd, kon met sap worden overgebracht.BehalveChenopodium foetidum enSonchus oleraceus bleken ook 23 van de 34 getoetste soorten uit de familie Solanaceae vatbaar voor dit virus te zijn. Gezuiverde virus preparaten bevatten isometrische deeltjes met een diameter van 27 nm (Fig. 2) Het virus bestaat uit twee deeltjes met sedimentatie-coëfficiënten van 112 en 50 S. Het 112 S deeltje bleek infectieus te zijn, het andere niet. Op grond van de sedimentatiecoëfficiënten kan worden berekend dat het 112 S deeltje 38% nucleïnezuur bevat. Voor de basenverhouding in het nucleïnezuur werd 22,9% adenine, 14,4% guanine, 37,2% cytosine en 25,5% uracil gevonden (Tabel 1). Het hoge gehalte van cytosine kwam ook tot uiting in de U.V. absorptiekromme van het virus en het nucleïnezuur (Fig. 1). Het gezuiverde virus bleek zeer infectieus te zijn; 6000 deeltjes/ml waren in staat een plant van de soortNicotiana clevelandii ziek te maken.Op grond van serologisch onderzoek kon het virus tot de turnip yellow mosaic virus groep worden gerekend. Het vertoonde serologische verwantschap met de Andean potato latent virus (APLV) subgroep (Tabel 2). In premunitieproeven bood het slechts een geringe bescherming tegen APLV en dulcamara mottle virus. Het omgekeerde werd eveneens geconstateerd. De leden van de APLV-subgroep kunnen op grond van hun waardplantenreeks van elkaar onderscheiden worden (Tabel 3).     

香蕉上的新纪录雪松毛刺线虫描述

本文对中国云南河口香蕉上的雪松毛刺线虫(Trichodorus cedarus Yokoo)的形态特征进行了描述,其测计值与我国文献记载的杉木、桃、苹果和梨树种群相关测计值比较,香蕉种群的雌雄虫虫体平均长度和b值偏大,口针平均长度较杉木和桃上种群的短,长于苹果和梨树上的种群。该线虫在香蕉根围土发现尚属首次。