Citrus Huanglongbing: The Pathogen and Its Impact

Fig. 30. Cumulative assessment of spatial patterns of visual and PCR analyses in five plots in south Florida. (Top) Nearest-neighbor distance between visually HLB symptomatic trees and HLB trees that are RT-PCR positive parsed into 25 ft categories. (Bottom) Cumulative distribution of nearest neighbor distance indicated (at top) with indication that 90% of RT-PCR positives occurred within 125 ft of a tree with visual symptoms.



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