How does Phytophthora spread?

Phytophthora, a plant pathogen known for causing significant diseases, particularly in crops and ornamental plants, primarily spreads through swimming spores called zoospores. These zoospores are capable of moving in water and can infect plants when they come into contact with them. The mycelium can also persist in the soil or decaying plant material, allowing it to infect new plants when conditions are favorable. Understanding this method of spread is crucial for managing Phytophthora diseases, as it highlights the importance of water management and sanitation in preventing outbreaks.

While the other options present possible methods of transmission, they do not accurately describe the primary spread mechanism of Phytophthora. For instance, spores carried by insects or wind would involve different types of pathogens, and direct contact with infected plants while relevant for disease transmission does not encompass the pathogen's primary locomotion method. Thus, recognizing the role of zoospores in water facilitates the effective management of Phytophthora in agricultural and ornamental contexts.