Fitopatologia Brasileira (2005) 30, 504-509

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Gabriela C.G. Andrade, Acelino C. Alfenas, Reginaldo G. Mafia, Luiz A. Maffia and Rivadalve C. Gonçalves (2005)
Escala diagramática para avaliação da severidade da mancha foliar do eucalipto causada por Quambalaria eucalypti
[Diagrammatic scale for assessment of eucalyptus leaf spot severity caused by Quambalaria eucalypti]
Fitopatologia Brasileira 30 (5), 504-509
Abstract: The leaf spot, caused by Quambalaria eucalypti, is presently one of the most serious diseases in eucalyptus (Eucalyptus spp.) nurseries in Brazil. Since the disease was only reported recently in Brazil, little is known about its epidemiology and control. As standardized and precise methods are needed for the disease severity evaluations, a diagrammatic scale containing eight levels (0,4; 1; 2; 4; 8; 16; 32 and 49%) of severity was developed in this study for the disease quantification. For the scale validation four inexperienced and four expert appraisers scored leaves with different levels of severity, initially without the use of the scale and later on with its use. The estimates were compared for accuracy and precision. Using of the scale the appraisers were able to get better levels of precision and accuracy. After training, the levels of precision and accuracy were also increased, mainly for the inexperienced appraisers. The greatest errors in the disease evaluations were observed between levels 15 and 30% of severity.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Portuguese)
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Database assignments for author(s): Acelino C. Alfenas, Luiz A. Maffia

Research topic(s) for pests/diseases/weeds:
surveys/sampling/distribution


Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.


Quambalaria eucalypti Eucalypt (Eucalyptus) Brazil (south)