University of Illinois Extension
University of Illinois Extension - Selecting Trees for Your Home
Cedar Rust Diseases
Hawthorn rust on crabapple leaf and fruit
Severity: out of 5
Frequency: out of 5

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.

Cycle: See this chart for life cycles of the three juniper rust diseases
Management: Contact your local University Extension office or local garden center.
Associated trees: