Seasonal Activity of Phytophthora Diseases

Several species of Phytophthora damage nursery crops in Oregon. The season when a given disease is most active depends on each pathogen's biology, the host, and the environment. The following chart shows six of the most common species found in both field and container nurseries. These are broadly categorized as warm-season or cool-season pathogens. Note that the P. citricola species complex has recently been split into several species including P. plurivora and P. multivora.

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