Citrus Huanglongbing: The Pathogen and Its Impact

Fig. 26. Hamlin sweet orange planting in São Paulo state, Brazil demonstrating rapid spread of HLB over 9 to 10-month period. White squares are healthy trees, red squares are HLB-diseased trees determined via visual assessment. Older commercial citrus blocks to the north and west were heavily infected with HLB which acted as inoculum sources for new infections within the block.



Image from Plant Health Progress article:
Citrus Huanglongbing: The Pathogen and Its Impact