An overview of citrus canker in Brazil

Abstract

Citrus growers in several states of Brazil, but mainly in São Paulo (SP), have battled during 60 years against citrus canker (Xanthomonas citri subsp. citri) using exclusion and eradication methods. Since its first detection in 1957, the eradication program has undergone many modifications and efforts were made to suppress rather than eradicate the disease. When the eradication protocols became less strict during the late 2000s and early 2010s, the number of canker-affected citrus orchards in SP, the largest orange-producing area in the world, started to set consecutive records annually. In addition, research data and experiences in the citrus-producing regions, where the disease has been managed successfully, encouraged the adoption of a similar strategy in Brazil. Given the expansion of the disease in the country and its non-homogeneous distribution across the states, a new federal legislation came into effect in 2017. Since then, each state can define a status regarding the presence and control of citrus canker: (i) area with no occurrence, (ii) pest-free area, (iii) area under eradication, and (iv) area under risk mitigation. The establishment of an official status is not mandatory for the state, but those with an undefined status are not allowed to market fruit to other states and countries. For the first time, the disease can be managed without the need to eradicate the citrus trees in canker-affected areas even at high incidence, given that no serious losses due to citrus canker are expected if the recommended control measures are properly followed. An historical overview of the eradication program, the current legislation, and the status of citrus canker for all states in Brazil are reviewed.