University of Illinois Extension

University of Illinois Extension

Hort Answers

Fungal Disease

Cedar Rust Diseases

Hawthorn rust on crabapple leaf and fruit
Hawthorn rust on crabapple leaf and fruit

Host vary by pathogens - for additional information on three juniper rust diseases that is compared to each other - see this chart

Plants Affected

There are several rust diseases that attack junipers. Somejunipers are more resistant than others. Cedar Apple and Cedar Hawthorn rust tend to make a roundish brown gall on the branches. After the disease finishes sporalating (orange, jelly-like telia stage) in the spring, the twig may or may not die. Quince rust looks more like a roughened but slight swollen area in the twig. The quince rust fungus tends to sporalate multiple years from these infected areas before dying.

Controls include preventive sprays, growing resistant varieties and pruning out the galls before they sporulate. For additional information on these three rust diseases as well as a chart that compares these three rusts, check the fact sheets.

Life Cycle
See this chart for life cycles of the three juniper rust diseases

Contact your local University Extension office or local garden center.

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