WSU Extension


Caption: Pear rust
Photo by: R.S. Byther
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Pear : Pacific Coast pear rust
(revision date: 5/20/2014)

Pacific Coast pear rust is a fungal disease affecting pears, hawthorn, apple, crabapple, serviceberry, quince, and mountain ash. The alternate host is the incense cedar (Calocedrus decurrens), which develops witches' brooms. Infected fruits of pear are deformed and drop prematurely. On the surface of the fruit, yellowish spots with cup-shaped pustules develop. Leaves and green shoots may also be infected. Symptoms are most obvious after flowering and before July. For more information on pear rust diseases see Pear: Pear trellis rust.
Management Options

Non-Chemical Management
  • Avoid susceptible varieties such as 'Winter Nelis' and European and Oriental cultivars.
  • Collect and destroy fallen fruit beneath trees.
  • Plant resistant varieties such as 'Bartlett'.
  • Prune out and destroy rust-infected tissues in pears and alternate hosts.
  • Remove alternate hosts in the vicinity of pear trees, when practical.
Select non-chemical management options as your first choice!

Chemical Management

None recommended

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Caption: Pear rust
Photo by: R.S. Byther
Caption: Pear rust
Photo by: R.S. Byther
Caption: Pear rust fruiting bodies
Photo by: C.R. Foss