Diagrammatic scale to quantify the damage caused by bean thrips to the peanut crop

Abstract The objective of this work was to develop and validate a diagrammatic logarithmic scale to evaluate the damage caused by the Caliothrips phaseoli bean thrips to peanut (Arachis hypogaea). Leaflets of artificially infected peanut plants were collected, and the damaged leaf area (DLA) was calculated using the SisCob software. Six-, seven-, eight-, and nine-class scales were developed, and the range of each class was obtained with the 2-LOG software. The leaflets were analyzed by 12 raters using the four proposed scales. The scales were validated as to: precision and accuracy, using the linear regression between the DLA and estimated area; and reproducibility, by the linear regression between the estimations of the raters combined in pairs. The eight-class scale shows the best results in terms of accuracy and precision, as well as a high reproducibility.