Tom Creswell, Department of Botany and Plant Pathology, Purdue University
Kelly Ivors, Department of Plant Pathology, North Carolina State University
Mike Munster, Department of Plant Pathology, North Carolina State University
Phytophthora is one genus within the group of “fungus-like” organisms known as oomycetes. Phytophthora species are capable of infecting a wide range of trees, shrubs, and bedding plants. Most plant-pathogenic species of Phytophthora cause root and crown rots and are able to persist for numerous years in soil.
Chemical management of these diseases usually is impractical or not economical in landscapes. The following cultural management practices are recommended when Phytophthora root or crown rot has been diagnosed in a landscape.
• Remove severely affected plants.
• Prepare the site to ensure good drainage and organic matter content by adding pine bark to soil, raising beds, or planting on berms.
• Inspect all planting material and set only healthy plants into the landscape.
• Avoid overwatering and over-fertilization.
• Select plant species that are tolerant to Phytophthora when replacing plants lost to this pathogen.
Due to the large number of Phytophthora species and their wide host ranges, it is very difficult to make general recommendations about replacement plants for the landscape. The lists presented here were compiled based on published reports, Plant Disease and Insect Clinic records from North Carolina and neighboring states, and the expert opinion of many plant pathologists.
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