What disease is caused by Pythium sp.?

The disease caused by Pythium species is known as damping-off. This condition primarily affects seedlings and young plants, leading to their failure to germinate or survive. Pythium is a group of water molds that thrive in damp, cool conditions and primarily affects the root systems of plants. The pathogen can cause the rotting of seeds and stems at or just below the soil surface, which is why seedlings often collapse and die shortly after germination.

Damping-off is particularly problematic in nurseries and greenhouses, where conditions can be optimal for the pathogen's growth. This disease can occur in various plants, including vegetables and ornamentals, highlighting the importance of proper cultural practices, such as managing soil moisture, to mitigate its effects.

Other diseases listed, such as root rot, late blight, and powdery mildew, are caused by different pathogens or environmental conditions, making them distinct from damping-off caused specifically by Pythium.