Pseudoperonospora Cubensis - Host Specificity, Pathotypes

Host Specificity, Pathotypes

Within the cucurbit family, P. cubensis isolates will exhibit a specific host range, that is, it will infect certain cucurbits and not others. For example, if cucumber and squash are grown side-by-side sometimes only the cucumber is diseased. When a pathogen exhibits this type of host specificity within a plant family, it is referred to as a pathotype. At least five pathotypes of P. cubensis have been described in the U.S. More recent studies in the Czech Republic have revealed more pathotypes.