Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00000800
11/12/99
JUGLANS DISEASE PROBLEMS
Brown leaf spot or anthracnose symptoms are irregular dark
brown spots occurring in early summer. Severely infected
trees may be defoliated. Rake up and destroy infected,
fallen leaves.
Canker diseases cause dieback or death of trees. Infected
bark may be discolored, sunken, or have a different
appearance than surrounding healthy bark. Prune out
infected branches and keep trees healthy. If the canker
girdles the trunk the tree dies.
Bacterial blight causes small, irregularly shaped spots on
the leaves and leaf stems. Black spots occur on young
nuts and shoots. Nearly ripe nuts have large black spots
on the husks. Infected nuts fall prematurely or may have
husks, shells, and kernels blackened and ruined.
Powdery mildew causes a white coating on the leaves.
Chemical controls should not be necessary.
During periods of high temperature and drying winds,
walnuts will scorch. Make sure plants have adequate soil
moisture.
Related information.
Pesticide Recommendations
Cankers
Anthracnose
Powdery Mildew
Fungal and Bacterial Leaf Diseases
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to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
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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.
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