The distribution of Phytophthora cinnamomi in the Americas is related to its main host (Persea americana), but with high potential for expansion

Abstract

Phytophthora cinnamomi is among the most destructive plant pathogens that affect many host plants in different ecosystems. Economically important hosts of this pathogen include avocado (Persea americana), and this oomycete may cause large-scale destructive epidemics. This study analyzed the potential geographic distribution of P. cinnamomi (pathogen) and avocado (host), and distribution of the pathogen in relation to multiple hosts in the Americas. Niche overlap between hosts and pathogen were also evaluated, using a multistep process of ecological niche modelling and the MaxEnt algorithm. Niche similarity among pathogen populations in different hosts and related niche similarity were also examined. As a complement, a tool was designed to visualize the risk of this pathogen in avocado. Results showed that the pathogen was randomly distributed in the avocado niche environmental space, but the niche of the pathogenwas narrower than  that of its principal host. The niche of the pathogen was largely a function of the host niches. Areas with potential to grow avocado could present low risk of P. cinnamomi, but given the invasiveness of this pathogen, they may be affected in the future.