Node and percent diseased leaf area estimated from visual leafspot score. Keywords: Peanut, leafspot, disease assessment, defoliation, yield, crop modeling. lntroduction Assessment or measurement of disease is the basis of epidemiologr which is the study of disease at the level of populations of pathogens and hosts. Disease often has to exceed a certain threshold before it reduces the yield of a crop. The accuracy and precision of visual disease severity assessments can be improved by . quantitative disease/pathogen assessments in plant.


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Broadly speaking, until the s, plant pathology was considered as the applied side of mycology and, indeed, the Plant disease assessment Society of Plant Pathology was spawned from its mentor, the British Mycological Society, with considerable help from The Association of Applied Biology.

Current and Prospective Methods for Plant Disease Detection

Field assessment of plant derivative compounds for managing fungal soybean diseases. PCR depends on the efficacy of DNA extraction and the performance is affected by inhibitors plant disease assessment in the sample assay, polymerase activity, PCR buffer and concentration of deoxynucleoside triphosphate [ 20 ].

In addition, application of PCR for pathogen detection requires designing a primer to initiate DNA replication, which could limit the practical applicability of this technique for field sampling of diseases [ 19 ]. Fluorescence in-situ Hybridization Another type of molecular detection technique is fluorescence in-situ hybridization FISHwhich is applied for bacterial detection in combination with microscopy and hybridization of DNA probes and target gene from plant samples [ 21 ].

In addition to bacterial pathogens, FISH could also be used to detect fungi and viruses and other endosymbiotic bacteria that infect the plant [ 2223 ].


The high plant disease assessment and specificity of DNA probes provide high single-cell sensitivity in FISH, because the probe will bind to each of the ribosomes in the sample.

In addition to the detection of culturable plant disease assessment that cause the plant diseases, FISH could also be used to detect yet-to-be cultured so called unculturable organisms in order to investigate complex microbial communities [ 24 ]. For example, false positive results with autofluorescence materials are a common problem that often lowers the specificity.

Accuracy and reliability of FISH is highly dependent on the specificity of the nucleotide probes.

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Insufficient penetration, higher order structure of target or probe e. Enzyme-Linked Immunosorbent Assay The enzyme-linked immunosorbent assay ELISA is another molecular method for identification of diseases based on antibodies and color change in the assay [ 27 ]. In this method, the target epitopes antigens from the viruses, bacteria and fungi are made to specifically bind plant disease assessment antibodies conjugated to an enzyme.


The plant disease assessment can be visualized based on color changes resulting from the interaction between the substrate and the immobilized enzyme.

The performance of ELISA can be improved greatly with the application of specific monoclonal and recombinant antibodies which are commercially available [ 2829 ].

Diagnosis of Plant Disease

For plant disease detection, tissue print-ELISA and lateral flow devices that enable detection have been fabricated for on-site detection. Immunofluorescence Immunofluorescence IF is a fluorescence microscopy-based optical technique used for the analyses of microbiological samples.

The technique can also be utilized to detect pathogen plant disease assessment in plant tissues.

For this technique, plant samples are fixed to microscope slides in thin tissue sections. Detection is achieved by conjugating a plant disease assessment dye to the specific antibody to visualize the distribution of target molecule throughout the sample [ 30 ].

Field assessment of plant derivative compounds for managing fungal soybean diseases.

IF has been used to detect onion crop plant disease assessment by a fungus Botrytis cinerea [ 31 ]. It is from this diversity that presumably the most potent instrument for disease management has been developed by plant pathologists: Host plant diversity, and the disease resistance genes it harbours, can be deployed over plant disease assessment and space, according to epidemiological principles.

Sustainable production and protection systems also need to be devised which could exploit scarcer resources sparingly, and if possible enhance the resource base. We are experts plant disease assessment integrated pest management for the control of plant diseases, pests and weeds.