Symptoms

• Rust on fruit trees typically presents as yellow spots, about 1/8 inch in diameter, often on the underside of leaves. If left untreated, rust can turn into orange lesions with a black dot in the center.
  
  

Effects

• The fruit on a tree with rust can become diseased, and fruit will often fall from the tree before harvest. In addition, the fruit yield will be reduced for the current and following year. The tree may also suffer from premature defoliation and become generally weakened.
  
  

Treatment

• If an infected juniper tree is planted near the rust-infected fruit tree, removing the juniper may clear up the rust on the fruit tree. In addition, fungicides can be applied in the spring at the first sighting of rust. Fungicides should be applied every 7 to 10 days until symptoms subside.