Spatio-temporal analysis of the citrus variegated chlorosis (CVC) in the Northwest of Paraná, using PCR for detection of Xylella fastidiosa - DOI: 10.4025/actasciagron.v28i3.967

Abstract

Countless diseases affect the citriculture, as the citrus variegated chlorosis (CVC) which is caused by the bacteria Xylella fastidiosa. The aim of this work was to determine the space distribution of the disease inside commercial orchards in the Northwest of Paraná, using molecular methods. Symptomatic orchards were selected for CVC with the varieties 'Pêra', 'Valência' and 'Folha Murcha' (Citrus sinensis Osbeck). For each variety, 4 positive reference-plant for CVC (presence of CVC symptoms or molecular analysis by PCR) and 8 plants around of each one reference-plant were evaluated, totaling 36 plants for variety. The detection of the bacteria was conduced by Polimerase Chain Reaction (PCR) technique. Simultaneously, evaluations through visual symptoms of CVC were conducted. The results of the temporal analysis were obtained using the Monomolecular, Logistic and Gompertz models. The Logistic model was the one that best fit to describe the behavior of the disease in the time, for all the studied varieties. Data showed that the space behavior of the disease differed when the same area was evaluated by visual and molecular methods, resulting in a difference in the space pattern of the evaluated areas. Therefore, the two used methods, symptoms and PCR, were capable of verifying these changes in the presented space pattern, but the molecular analysis (PCR) was better at detecting the happened changes.