Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00000638
11/12/99
FRAXINUS DISEASE PROBLEMS
A rust disease caused by Puccinia sparganioides causes
distorted leaves and swollen twigs. Small, yellow,
cup-like structures, producing yellow spores, appear on
the infected areas. The disease is rarely serious enough
to warrant chemical control.
A number of fungi cause leaf spots on ash. The disease is
worse in wet years and is partially controlled by
gathering and disposing of diseased, fallen leaves.
Anthracnose, caused by Gloeosporium aridum, is also called
leaf scorch and leaf spot. Infected parts of the leaves
turn brown (Vis. 1), especially along the margins. Infected
leaves fall prematurely. Rake up and destroy infected
leaves.
Canker diseases cause branch dieback and death of the tree
when the trunk is infected. There is no chemical control
for canker diseases. Try to keep trees healthy with
regular fertilization.
Powdery mildew makes a white coating on the leaves.
Ash ring spot virus causes chlorotic green and reddish
spots on the leaves. Leaves may also have ring spot in
ring or line patterns. Infected trees may be stunted and
dieback.
Verticillium wilt causes branches of infected trees to
wilt and die, eventually the entire tree may die. Keep
trees healthy.
Related information.
Pesticide Recommendations
Anthracnose
Cankers
Verticillium Wilt
Powdery Mildew
Fungal and Bacterial Leaf Diseases
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endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
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This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
For more information about this data base or its contents please contact
heatley@msue.msu.edu . Please read our
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