White Powder on Agapanthus

Identification

• The white powder on agapanthus is the result of a fungal growth referred to as powdery mildew disease. Powdery mildew is among the common plant diseases caused by numerous fungi. The disease is common in plants growing in overly humid conditions.

Damage

• The disease is characterized by the appearance of a white to gray powder coating on foliage. The powder is composed of very fine threads of fungal growth. With progression, the growth expands to stems and flowers and develops a mat-like, cottony texture. Disease stunts plant growth and distorts foliage and flowers. There is a general decline in plant health.

Control

• Taking preventative measures is among the best management strategies. Avoid growing plants in areas of poor ventilation, high humidity or low light, as these favor fungal growth. Start the use of recommended fungicides on initial signs of disorder. These include potassium bicarbonate, sulfur or Bacillus subtilis.