Epidemiological behavior of bacteria causing apical necrosis and tip drought in Eucalyptus seedling nursery miniprouts

The success of forest plantations depends, among other factors, on the quality of the planted seedlings and this can be evaluated according to quantitative parameters, such as height and diameter, as well as qualitative, such as phytosanitary aspect. Among the diseases described in nurseries, there are those of bacterial origin, such as vascular wilt caused by Ralstonia solanacearum, leaf spots attributed to Pseudomonas spp. and Xanthomonas spp. and the bacterium that causes die back (Enterobacteria). The last one is a new disease and little is known about its etiology, epidemiology and control. In this study, a rating scale was developed to evaluate the incidence and severity of the Enterobacteria and epidemiological studies, damage assessment, losses and disease control were performed. Therefore, it was concluded that this bacteriosis is not of annual incidence and was observed the most incidence in the months of February, March, April, May and December. The disease was able to reduce the production of sprouts per infected minicep by 20%, generating a loss of about U$500,00 per month of incidence. Higher temperatures were favorable for the pathogen development, as well as the incidence of rainfall. This can be explained by leaf wetness, which facilitates the spread of the pathogen from sick to healthy plants. Moreover, chemical control was not efficient, which demonstrates the importance of genetic studies and other biological control methods.