REVIEW Overview of citrus huanglongbing spread and management strategies in Brazil Renato Beozzo Bassanezi 1 & Sílvio Aparecido Lopes 1 & Marcelo Pedreira de Miranda 1 & Nelson Arno Wulff 1 & Haroldo Xavier Linhares Volpe 1 & Antonio Juliano Ayres 1 Received: 18 November 2019 /Revised: 20 March 2020 /Accepted: 26 March 2020 # Sociedade Brasileira de Fitopatologia 2020 Abstract Huanglongbing (HLB) has been a serious threat to the citrus industry worldwide. After its first report in São Paulo State, the main citrus production area in Brazil, the disease spread to the States of Minas Gerais, Paraná and Mato Grosso do Sul. Attempts to cure plants or remiss disease symptoms and damages have been evaluated and showed to be inefficient and nonviable. The development of resistant or tolerant varieties to the bacteria or its insect vector, the Asian citrus psyllid Diaphorina citri, is still a long term challenge. Earlier HLB management has been based on preventive measures such as planting of healthy nursery trees, elimination of diseased trees, and vector control. Supported by both research data and citrus grower experiences, HLB manage- ment in São Paulo and Triângulo/Sudoeste Mineiro citrus belt has been improved from measures individually applied only into the orchards to regional disease management, including differentiated psyllid control in the orchards based on tree location and shoot flushing, area-wide coordinated control of psyllids, and removal of inoculum sources in noncommercial properties in the vicinity of commercial orchards. In addition, the negative impact of HLB on orchard production and longevity has been reduced with wide adoption of better cultural practices such as high-density planting, irrigation, and adequate nutrition. Unlike in other countries where HLB reached epidemic levels, the management of HLB in São Paulo and Triângulo/Sudoeste Mineiro citrus belt has been considered a success case and has ensured the maintenance of citrus production and competitiveness of the Brazilian citrus industry while new, more durable, and sustainable measures are not yet available. Keywords Citrus greening . Disease incidence . Disease impact . Disease epidemiology . Disease management Introduction Citrus huanglongbing (HLB or citrus greening), known since 1870 in Southeast Asia (Lin 1956), is considered the major threat to citrus industry worldwide because of the rapid spread, severe damage to citrus production and fruit quality, and the difficulty of control (Bové 2006). HLB was first reported in Brazil in 2004 (Coletta-Filho et al. 2004; Teixeira et al. 2005a). Initially, the disease was limited to the municipalities located in the center of Sao Paulo State. ‘Candidatus Liberibacter asiaticus’, the bacterium spe- cies described as the associated agent of HLB in Asian coun- tries, was rarely detected in these early cases. Less than 2% of leaf samples that showed typical symptoms of HLB, namely, diffuse and asymmetrical chlorosis (known as leaf mottling), contained 'Ca. Liberibacter asiaticus’. The common agent that was present in over 98% of the ‘Ca. Liberibacter’-positive samples was a new organism, since characterized as a new species of ‘Ca. Liberibacter’ and named ‘Ca. L. americanus’ (Teixeira et al. 2005a, b). However, within four years, this scenario completely reversed and ‘Ca. L. asiaticus’ became the predominant species in all São Paulo orchards (Lopes et al. 2009a), and other locations where HLB was detected in the Americas. Currently, ‘Ca. L. asiaticus’ is present in over 99.9% of all ‘Ca. Liberibacter’-positive field samples ana- lyzed at the Fund for Citrus Protection (Fundecitrus) diagnos- tic laboratory. This rapid shift in ‘Ca. Liberibacter spp.’ prev- alence seems to be associated with differences in some char- acteristics that give ‘Ca. L. asiaticus’ important epidemiolog- ical and competitive advantages over ‘Ca. L. americanus’. The first species tolerates higher temperatures and reaches higher titers in plant tissues, which favors acquisition and * Renato Beozzo Bassanezi renato.bassanezi@fundecitrus.com.br 1 Department of Research and Development, Fundecitrus, Araraquara, SP, Brazil Tropical Plant Pathology https://doi.org/10.1007/s40858-020-00343-y