Spots on My Impatiens' Blooms

Impatiens are widely used as bedding plants.

Impatiens (Impatiens wallerana) are summer flowering annuals or perennials that bloom in shades of purple, orange, red and pink. The plants attract hummingbirds and thrive in areas of partial to full sun. A fungal disorder leads to spots on the flowers.

Identification

Impatiens are susceptible to bacterial leaf spot and soft rot caused by Erwinia pseudomonas and Xanthomonas spp. The disease-causing fungi often start to affect the vascular tissues in plant and cause plants to die entirely.

Damage

Initial symptoms of disease include appearance of small, water-soaked spots on flowers, foliage and stems. Gradually, the spots enlarge and turn dark gray to black with yellow margins. Affected tissues start to decay and have an unpleasant odor. Stems develop cankers. Entire plant slowly decays and dies.

Control

Obtain disease-free and healthy plants from reliable sources and do not plant too deeply. Choose well-ventilated areas for planting and avoid unnecessarily injuring plants. If you are sure of infection, it is best to remove the diseased plant early. Use the more resistant varieties.

References

• University of California Extension: Bacterial Leaf spot and Soft Rot
• University of California Extension: Bacterial Soft Rots, Leaf Spots, Blights and Wilts