Cedar apple Rust (the orange stuff)

Description:

Description Cedar-apple, cedar-hawthorn, and cedar-quince rust are common diseases of apple and flowering crab. These rust fungi spend a portion of their life cycle on rosaceous hosts such as apple, flowering crab, and hawthorn, and another portion on species of Juniperus (which includes eastern red cedar). These rust fungi can result in considerable damage to rosaceous plants by causing premature defoliation and fruit distortion and abortion. The effects of these diseases on junipers are minimal. http://www.treehelp.com/trees/juniper/ju...

Habitat:

Limestone soil in mixed woodland