Powdery mildew on poinsettia
Updated: March 16, 2021

Symptoms of powdery mildew on indoor plants

  • There are several fungal species that cause powdery mildew of indoor plants, but the symptoms are the same.

  • The most obvious symptom is the white powdery coating on the surfaces of infected leaves and stems.

  • The initial areas of mildew may start out as small spots of powdery white growth before growing together to form a white coating over the entire surface.

Management strategies

  • Individual infected leaves can be picked off and destroyed.

  • Any method that will lower the humidity, or increase air circulation will help to lessen the chances of infection.

  • Space plants so that air can circulate between them to help reduce moisture.

  • Registered fungicides can be used, but in most home conditions, removal of infected plant parts and adjustment of environmental conditions to promote better air circulation should help.