Citrus Huanglongbing: The Pathogen and Its Impact

Fig. 29. Spatial Patterns of visual and PCR analyses in five HLB-infected plots in south Florida. Medium blue indicates plants with visual symptoms of HLB and RT-PCR positive, dark blue indicates plants with visual symptoms but RT-PCR negative, and light purple indicates plants without visual symptoms and RT-PCR positive.



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