Research Summary Abstract
Phytophthora species are destructive, fungus-like plant pathogens (oomycetes) that cause diseases such as root rot, crown rot, stem lesions, and foliar blight across a wide range of environmental horticulture crops. In nurseries, greenhouses, and landscapes, infections can reduce plant quality and vigor, cause significant plant losses, and spread through contaminated plants, soil, water, and production materials. This summary report compiles IR-4 research observations across multiple products, crops, production systems, researchers, and target species.