Which plant is most commonly affected by Plasmodiophora brassicae?

Plasmodiophora brassicae is a soil-borne protist that specifically targets members of the Brassicaceae family, commonly known as the mustard or cabbage family. This pathogen is well-known for causing clubroot disease, which predominantly affects cabbage, cauliflower, broccoli, and other related crops.

Cauliflower is particularly susceptible to this pathogen, exhibiting stunted growth and the formation of galls on the roots, which significantly impairs the plant's ability to take up water and nutrients. The life cycle of Plasmodiophora brassicae involves soil conditions that favor its growth, including high moisture and specific pH levels, making it crucial for those cultivating cruciferous crops to manage soil health and disease prevention strategies.

In contrast, the other options—tomato, spinach, and peas—are not primary hosts for Plasmodiophora brassicae. Tomatoes and peas belong to different plant families and are not typically affected by this specific pathogen, while spinach, although it can face various diseases, does not have significant interactions with Plasmodiophora brassicae. Therefore, recognizing cauliflower as the most commonly affected plant is essential for understanding the impact of this pathogen and effective management practices in agricultural settings.