Apple Doctor

Accessibility


| Share

Cedar Apple Rust

Authors: Aaron Bergdahl, Joseph Zeleznik

Symptoms

  • Disease affects cedars, junipers, apples, and crabapples.
  • Yellowish-orange lesions develop on leaves and fruit of infected apple/crabapple trees. Juniper-infecting spores develop in these lesions.
  • New infections on junipers result in small galls (or witches'-brooms) that, in moist conditions produce orange gelatinous structures that infect apple/crabapple hosts.

 Cedar Apple Rust - Esther McGinnis

Figure 1. Yellow to orange lesions are smooth on top of the leaf (Esther McGinnis, NDSU)

Cedar Apple Rust - Esther McGinnis

Figure 2. The spore-producing structures are raised on the back of the leaf (Esther McGinnis, NDSU)

Cedar Apple Rust - Aaron Bergdahl

Figure 3. Cedar apple rust fruiting bodies on juniper (Terry S. Price, Georgia Forestry Commission, Bugwood.org)

 

Management and other important facts

  • Do not plant the juniper/cedar and apple hosts closely together because both are required for infection.
  • Picking the galls or pruning the witches'-brooms off the junipers may mitigate the disease.
  • Several species of this pathogen are found in North Dakota. 
  • Several apple and crabapple cultivars are resistant to cedar-apple rust.

 

 

 

This website was supported by the U.S. Department of Agriculture’s (USDA) Agricultural Marketing Service through grant 14-SCBGP-ND-0038.
Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.