What Is Pythium in Plants?

Pythium is a fungus-like organism, similar to, but also distinct from fungi. Like a fungus, Pythium grows and colonizes a plant by producing hyphae (singular hypha), threadlike, filamentous cells that extract nutrients from the host plant. When hyphae from opposite mating types meet, they produce thick-walled oospores.

What causes Pythium?

Pythium blight is easily spread by moving water and mechanical equipment. It can travel on the blades of a lawnmower and on the soles of shoes. The fungus thrives in water-logged, poorly drained grass. It also loves over-fertilized, alkaline (pH over 7) soil with high levels of nitrogen and low levels of calcium.

Where is Pythium found?

Some species of Pythium are found in field soil, sand, pond and stream water and their sediments, and dead roots of previous crops.