Bringing the lab to the field:

Phytophthora pathogens cause root and crown rots in many ornamental species and are a recurrent challenge in nursery production. These pathogens greatly affect plant health, resulting in devastating losses to the nursery industry, and have the associated risk of releasing pathogens of regulatory concern into trade and natural ecosystems. Efforts to control pathogen spread are costly, and as such, developing reliable and fast diagnostic tools to prevent and monitor pathogen introduction into nursery production is key. 

A rapid and accurate method for the detection of Phytophthora is the recombinase polymerase amplification (RPA) assay. The Del Castillo Lab has validated and implemented this method for the detection of different Phytophthora species from plant tissue, and we are currently optimizing this assay for detection directly from water. Water surveillance can be implemented as an early detection and monitoring tool to assess if Phytophthora pathogens are present in a nursery facility. Currently, our research is validating assay robustness for different Phytophthora species in the presence of organic matter at a laboratory scale (see video). 

To evaluate assay implementation in nursery commercial settings, we are evaluating detection efficacy in artificially inoculated water at nursery scale collection tanks (Figure 1) and untreated, recirculated nursery water (Figure 2). 

The findings from this project will be valuable to the nursery industry, providing improved tools for early detection of Phytophthora species and preventing pathogen spread into trade and natural ecosystems.

This project is being carried out with support from a Cooperative Agreement from the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS), PPA 7721 under award number 10025-PPQS&T00-25-0133, and by the Plant California Alliance.