Agro-climatic favorability zones for sugarcane orange rust as a tool for cultivar choice and disease management

Abstract Australia and Brazil are among the most important sugarcane producers in the world. Even under favorable climatic conditions, the yields in these regions are often limited by several factors, including fungal diseases. Sugarcane orange rust (SOR), caused by Puccinia kuehnii, is one of the most severe fungal diseases and can cause extensive losses in susceptible cultivars. Considering the significant influence climatic conditions can exert on SOR, the present study had as its aims, firstly, evaluation of weather data during SOR epidemics in the state of Queensland, Australia, in 1999/2000, and the state of Sao Paulo, Brazil, in 2009/2010; and secondly, development of a predictive model for SOR occurrence and severity, for identifying agro-climatic favorability zones for this disease in these regions. The results showed that SOR climatic favorability was highest on east of Queensland and in the center-east region of Sao Paulo, where air temperature and humidity were favorable for the epidemics. This information can help growers to avoid the use of susceptible cultivars in those zones where SOR poses the greatest risk, and to optimize strategies for chemical control of the disease.