Agriculture & Natural Resources

Ash Rust

Severe symptoms of ash rust affecting leaves and twigs
Severe symptoms of ash rust affecting leaves and twigs, R. Mulrooney image

Rust has been severe this spring on ash trees, characterized by leaf spot and orange sporulation of the rust fungus on leaves and twigs. Severe infections can result in distortion to twigs and leaf drop later in the spring and summer. Ash rust is difficult to predict each year, due to inability to predict spore influx from the alternate host of marsh grass. Fungicide control is generally not recommended, but preventative sprays may be used on high value specimen trees Ash rust will not kill tress, but does contribute to stress on trees.

See the fact sheet at the link: PP-46 Ash Rust 2012

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