Elaboração e validação de escala diagramática para repilo em oliveira

Abstract

The olive cultivation in Brazil has been increasing in area and production for its high profitability of the final product and the benefits that olive offers to human health. The leaf fall in olive, also known as peacock eye, is among the most important diseases of olive groves and cause defoliation, resulting in progressive weakening of the plant. In this sense, the present study aimed to develop a DAS, able to increase the accuracy and precision of the severity estimates of fungus pathosystem Fusicladium oleaginum (syn. Spilocaea oleagina or Cycloconium oleaginum), in subtropical wet weather condition. The plants used in the work are in the experimental orchard of the Federal University of Technological in Paraná, Campus Pato Branco. The installed cultivars are Arbequina, considered low tolerance of leaf fall and Koroneiki characterized as resistant of leaf fall. Both olive cultivars were deployed in December 2011, at a spacing 5 x 2, handled with an annual pruning to remove the poorly located branches. The weed control was done with mowing and chemical control. It was not done fungicide application during the experiment. The DAS was developed with 6 levels: 1, 3, 6, 9, 12 and 15%. For validation of DAS, 50 sheets of images were used with known severity, evaluated by 8 inexperienced evaluators, with and without use of the proposed scale. It was observed that, with the help of the scale, for most of the evaluators, there was a reduction of absolute errors, reduction of lowest detectable value and consequently greater accuracy and precision of the estimates. The proposed DAS was considered adequate to estimate the severity of OLS in olive and can be used for epidemiological studies, evaluation of control strategies and selection of cultivars and resistant genotypes.