The Xylella fastidiosa bacteria has been more intensively studied in coffee plants since the first time it was noticed infecting this specie. However, it is not well known the damages it causes, once both bacteria and hostplant can co-habit for long periods (several years), as coffee plants seems to support this pathogen under determined conditions. The main objective of this work was to study the severity of the X. fastidiosa infection on grafted or not grafted coffee plants, evaluating external symptoms in several cultivars, grown under field conditions in two contrasting environments. The symptoms were evaluated in a notation scale of 1 to 4, being 4 given to the most severe symptoms. Under moisture stress in both Mococa and Garça, there were no differences among cultivars, however, during the rainy period, symptoms were more intense in 'Catuai' and 'Mundo Novo' not grafted cultivars during the 2000 growth season, as compared to the grafted ones. Not grafted 'Catuaí' was more severely attacked in Mococa than in Garça. The 2002 drought period in Garça was much longer and more severe than that of 2000 and 1998 in Mococa. However, there was less severe symptoms in Garça in 2002 demonstrating that moisture deficit is not the sole factor determining external bacterial symptoms, other physiological and environmental stresses and its interaction might probably play an important role in the coffee plant response to this bacteria infection.
coffee plants; morphology; Xylella fastidiosa; severity symptoms; seasonal variations
