Are plant pathogens entering nurseries from wildland forests? Are native plant nurseries serving as pathogen gateways?
Phytophthora ramorum and other invasive pathogens have raised awareness of the interconnections between nurseries and wildland forests and the significance of the nursery plant pathway for the movement and establishment of plant diseases in the USA. Over the past several years in California, P. tentaculata has been detected in native plant nurseries and outplanted at restoration sites but how it entered the native plant nurseries is not known. In WA state, P. chlamydospora is commonly detected in streams and nursery ponds and has been found to infect ornamental nursery stock. It is not known to what extent P. chlamydospora causes disease on PNW native plants and whether these plants are a reservoir of the organism that can then move into nurseries via infested stream water.
These are just a few examples of the porous boundary between wildlands and both native plant and horticultural nurseries. Pathogens can move in water, on seed or animals, in soil and plants themselves leaving nurseries and forests vulnerable to pathogen introduction. To prevent pathogen introductions along these pathways, we need to better understand the modes and directions of movement and incidence of pathogens. In this multi-state project we will survey for pathogens in restoration sites, forest plantations, native plant nurseries, and horticultural nurseries where plant production serves as a “crossroads” for potential pathogen movement. All sample collection locations will be kept confidential.
The overall goal of this project is to protect U.S. nurseries, communities and wildlands from damaging plant pathogens by improving our understanding of human- assisted pathogen movement in areas where propagative material collection, plant production or outplanting serve as a connection.
For more information contact Marianne Elliott
Information on ecology and management of soil-borne Phytophthora species, with an emphasis on nursery and restoration plantings