An Epidemiological Comparison of the US and Canadian <i>Plum pox virus</i> Eradication Programs

Fig. 2. Ripley’s L function analysis, a measure of spatial dependence, for PPV-positive Prunus blocks detected in Ontario in (A) 2006, (B) 2007, (C) 2008, and (D) 2009. A random labeling null hypothesis was used to account for the underlying pattern of all Prunus blocks.



Image from Plant Health Progress article:
An Epidemiological Comparison of the US and Canadian Plum pox virus Eradication Programs