Eucalyptus rust climatic risk as affected by topography and ENSO phenomenon

Abstract

Brazil is among the most important Eucalyptus producers in the world, contributing with approximately 25% of the world′s Eucalyptus plantations area. Even under favorable climatic conditions, the Eucalyptus yields in Brazil are often limited by several factors, including fungal diseases. Among others, Eucalyptus rust, caused by Puccinia psidii, is the one of the most severe fungal diseases and can cause extensive losses in wood production. Considering the significant influence of climatic conditions on Eucalyptus rust, this study aimed to analyze the effect of climatic variability, El Nino Southern Oscillation phenomenon (ENSO), and topo-climatic conditions on the favorability zones for Eucalyptus rust in south-central Brazil. The assessment of the climatic favorability for Eucalyptus rust was carried out for the main Eucalyptus producing regions in Brazil. For that, information related to climate, seasonal and inter-annual climatic variability, and disease response to topography effect were considered. The ENSO phenomenon affects the favorable climatic zones for Eucalyptus rust occurrence in a different way for the studied regions. For SC and PR states higher rust occurrence was observed in El Nino years and reduced in La Nina years while for the other states no trend was observed. The effect of topoclimatic conditions established in this study indicated its influence on the areas of climatic favorability for Eucalyptus rust occurrence. The results indicated that within favorable areas to the disease, it is possible to identify areas of low risk (escape areas) depending on the face of the terrain. This finding highlights the importance to consider the topo-climatic effect and ENSO phenomenon on plant disease monitoring and management.