*******285********** Hollyhock diseases (Alcea sp.)-Hort Answers - University of Illinois Extension
University of Illinois Extension

University of Illinois Extension

Hort Answers

Fungal Disease

Hollyhock diseases
Alcea sp.

Hollyhock rust
Hollyhock rust
 
Frequency
3 (1 = rare 5 = annual)
 
Severity
1 (1 = very little damage 5 = plants killed)
 
Hosts
Hollyhock

 
Symptoms

Alcea sp. (Hollyhock) is often attacked by a rust disease. On hollyhock, the rust pustules are pin head in size and may vary from yellow/red to red to brown or gray. Severely infected leaves will die.

Leaf spot caused by Cerco sporella causes angular gray to black spots (older spots may have tan centers with brown margins). The spots may merge and tear leaving leaves with a shredded appearance.

 
Management
Fungicides and sanitation may help reduce both fungal infections.

 
Related Resources
Home, Yard & Garden Pest Guide
Illinois Commercial Landscape and Turfgrass Pest Management Handbook
U of IL - Distance Diagnosis through Digital Imaging
U of IL - Plant Clinic