Improving sooty blotch and flyspeck severity estimation on apple fruit with the aid of standard area diagrams     

Piérri Spolti  Luana Schneider  Rosa M. V. Sanhueza  Jean C. Batzer  Mark L. Gleason  Emerson Medeiros Del Ponte 《European journal of plant pathology / European Foundation for Plant Pathology》2011,129(1):21-29

Sooty blotch and flyspeck is caused by numerous species of fungi that colonize the surface of apple fruit and thereby lower its market value. Although this disease poses a substantial threat to apple growers’ profitability in some regions, reliable and cost-effective methods for epidemiological and disease control studies have not been validated, nor are they widely available. We modified a standard area diagram to aid sooty blotch and flyspeck severity assessments and quantified its impact on accuracy and precision of visual estimates. Samples of ‘Fuji’ and ‘Mutsu’ fruit were photographed both from the top and laterally. Severity was assessed from a sub-sample of 160 images using image analysis software. Validation of the diagram was performed by eight raters who independently assessed severity in two series of selected images representing the lateral view and the top view, initially unaided and subsequently with the aid of the scale. Severity estimates ranged from 0.4% to 98% (most fruit had <10% severity). Accuracy and precision of the estimates were significantly improved when using the diagrammatic scale; concordance correlation coefficient values increased from 0.81 to 0.95. A strong tendency to underestimate severity for the mid-range to high levels was minimized when using the aid, which also improved reproducibility of the estimates among raters. In addition to strengthening evidence that a standard area diagram can be used reliably in sooty blotch and flyspeck studies, we expanded its application to disease assessment in the peduncle region, which enhances the usefulness of the method for evaluating efficacy of management practices.  相似文献   

A rapid spectrofluorometric screening method for enrofloxacin in chicken muscle     

Chen G  Schneider MJ 《Journal of agricultural and food chemistry》2003,51(11):3249-3253

A simple spectrofluorometric method was developed for screening enrofloxacin (ENRO) in chicken muscle. A single-step extraction with acidic acetonitrile gave the best results without further cleanup. Following centrifugation the supernatants were excited at 324 nm and the emission was measured at 442 nm. Using this procedure, 18 chicken breast samples from 3 producers were tested. The results showed background signal levels significantly lower than those corresponding to 300 microg/kg ENRO, the FDA approved tolerance level. Statistical treatment of these data established a threshold which can be used in subsequent screening of ENRO at the tolerance level. The calibration curve revealed a satisfactory linear relationship (R(2) = 0.9991) in a range of 0-700 microg/kg ENRO in fortified chicken breast. ENRO-incurred samples were examined using this approach, and the results agreed with those obtained from more extensive separation followed by high-performance liquid chromatography. Because the threshold can be set at the 3 sigma limit, reliable screening can be accomplished with an error rate of less than 0.26%. Based on this investigation, a high-throughput screening method for ENRO in chicken tissue is proposed.  相似文献   

Effect of seeders and tillage equipment on vertical distribution of oilseed rape stubble     

Olivier Schneider  Jean Roger-Estrade  Jean-Noël Aubertot  Thierry Dor 《Soil & Tillage Research》2006,85(1-2):115-122

When the spreading of a disease depends on the proportion of infected residues remaining at soil surface it is of crucial importance to analyse the effects of tillage practices on the vertical distribution of stubble. This is the case with phoma stem canker (blackleg), whose epidemics are initiated in autumn, by air-borne ascospores released from stubble located at the soil surface. We compared initial vertical distribution of oilseed rape residues to those observed after sowing and various tillage operations (rotary harrowing, stubble disking, chiselling and mouldboard ploughing). Almost 20% of the initially buried residue was brought back to soil surface with seeding. Rotary harrow brought 40% of the residue buried in the 0–10 cm layer up to the surface and left unburied about 70% of surface residue. Stubble disking appeared to be more efficient for residue burial than chiselling. Mouldboard plough was the only tool that buried all residues. A simple model was developed that predicted burial and return to the soil surface of potentially infected residues as a function of tillage practices used after harvest. Simulation of different tillage sequences showed that the order in which tools were used also affected location of residues. Our results highlighted the importance of tillage in the cultural control of phoma stem canker and will contribute to the definition of integrated pest management strategies for oilseed rape.  相似文献   

Photodegradation of imidacloprid   总被引：4，自引：0，他引：4  

Wamhoff H  Schneider V 《Journal of agricultural and food chemistry》1999,47(4):1730-1734

The photolytic decomposition of the insecticide imidacloprid (1) in HPLC grade water and of imidacloprid as the formulated product Confidor insecticide in tap water was studied using HPLC methodology. The structures of several degradates have been determined in aquatic medium, and the DT(50) values of imidacloprid and Confidor have been measured. In addition, the influence of TiO(2) on the photodegradation of Confidor was studied. The photoproduct 1-(6-chloro-3-pyridinyl)methyl-2-imidazolidinone (5) has been identified as the main degradate in each of the three series of experiments by several analytical techniques. The photolytic half-lives for imidacloprid under the conditions of this study were 43 min in HPLC grade water, 126 min formulated as Confidor in tap water, and 144 min formulated as Confidor in tap water in the presence of TiO(2).  相似文献   

Rapid fluorescence screening assay for enrofloxacin and tetracyclines in chicken muscle     

Schneider MJ 《Journal of agricultural and food chemistry》2004,52(26):7809-7813

A simple, rapid fluorescence assay was developed for screening both enrofloxacin (ENRO) and tetracyclines in chicken muscle at the U.S. tolerance levels (300 ng/g and 2 microg/g, respectively). Screening for both classes of antibiotics is accomplished using one extraction, thus simplifying and expediting the process. The method requires an initial extraction of chicken muscle with 1% acetic acid in acetonitrile, centrifugation, and analysis of the supernatant for ENRO fluorescence. After addition of ammonium hydroxide, magnesium chloride, and methanol, followed by centrifugation and filtration, the supernatant can be measured for tetracycline fluorescence. Chlortetracycline (CTC) was chosen as a representative tetracycline to demonstrate the method, as it displays intermediate sensitivity among the three tetracyclines approved in the U.S. Comparison of the fluorescence of control and tolerance-level-fortified samples of both ENRO and CTC shows no overlap. Setting a threshold as the average fortified fluorescence minus 3sigma allows for successful screening, as illustrated with blind samples as controls or fortified with ENRO and/or CTC over a range of concentrations. This method can provide an alternative or supplemental approach to currently used microbial screening assays.  相似文献   

Measurement of nitrite and nitrate in blood   总被引：1，自引：0，他引：1  

N R Schneider  R A Yeary 《American journal of veterinary research》1973,34(1):133-135

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A serologic survey of veterinarians for antibody to feline leukemia virus   总被引：1，自引：0，他引：1  

R Schneider  J L Riggs 《Journal of the American Veterinary Medical Association》1973,162(3):217-219

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Morphological evidence of the interaction between plasma cells and macrophages in beagle dogs.     

P Schneider 《Veterinary pathology》1979,16(3):385-387

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Oral Immunisation of Foxes against Rabies: A Field Study     

F. Steck  A. Wandeler  P. Bichsel  S. Capt  L. Schneider 《Zoonoses and public health》1982,29(5):372-396

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Comparative prevalence of four enterotoxin genes among Escherichia coli isolated from swine   总被引：15，自引：0，他引：15  

H W Moon  R A Schneider  S L Moseley 《American journal of veterinary research》1986,47(2):210-212

Presence of Escherichia coli enterotoxin genes LT (heat-labile enterotoxin), STaP (heat-stable enterotoxin a, porcine genotype), STaH (heat-stable enterotoxin a, human genotype), and STb (heat-stable enterotoxin b) among 874 swine isolates of E coli was determined, using DNA probes and the DNA colony hybridization technique. Of the 874 isolates evaluated, 45% hybridized with at least one of the enterotoxin gene probes and were designated as enterotoxigenic E coli (ETEC). Eighty-five percent of the ETEC were from pigs with enteric colibacillosis. The remaining 15% were from pigs with edema disease or various other diseases, and from healthy swine. Seventy-four percent of the ETEC hybridized with the STb probe, 52% with STaP, and 31% with LT; ETEC did not hybridize with the STaH probe. Most of the ETEC hybridized with more than one enterotoxin gene probe. Isolates that hybridized with the LT probe also hybridized with STb. The most prevalent gene combination was LT-STb. However, 35% of the ETEC from neonatal (less than or equal to 1 week old) swine with enteric colibacillosis were of the STaP-only genotype, and 33% of the ETEC from older swine with enteric colibacillosis were of the STb-only genotype.  相似文献