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Deciduous Tree Leaf Disease Quick Reference

 

 

Anthracnose
Hosts:
  Most trees, commonly ash, maple and oak
Pathogens:  Gloeosporium spp. as well as other fungi
Signs/Symptoms:  Blotchy dead areas on leaves
For more information see:  Anthracnose
Purple-Bordered Leaf Spot
Host:
  Amur, Japanese, red, silver and sugar maple
Pathogen:  Phyllosticta minima
Signs/Symptoms:  Discrete, circular leaf spots with purple borders
For more information see:  Purple-bordered leaf spot
 Tubakia (Actinopelte) Leaf Spot
Hosts:
  Oak
Pathogen:  Tubakia spp. (Actinopelte spp.)
Signs/Symptoms:  Discrete circular, or irregular blotchy dead areas on leaves
For more information see:  Tubakia leaf spot
 Apple Scab
Hosts:
  Apple, crabapple, pear, mountain-ash
Pathogen:  Venturia inaequalis, V. pirina
Signs/Symptoms:  Circular, black leaf spots with feathery edges; eventual leaf loss
For more information see:  Apple scab
 Gymnosporangium Rusts
Hosts:
  Apple, crabapple, hawthorn
Pathogens:  Gymnosporangium spp.
Signs/Symptoms:  Bright yellow-orange, circular leaf spots
For more information see:  Gymnosporangium rusts
 image of white mildew on green leavesPowdery Mildew
Hosts:
  Most deciduous trees
Pathogens:  Several genera of powdery mildew fungi
Signs/Symptoms:  Uniform/blotchy powdery white areas on upper and lower leaf surfaces
For more information see:  Powdery mildew on trees and shrubs
 Downy Leaf Spot
Hosts:  Hickory, walnut
Pathogen:  Microstroma juglandis
Signs/Symptoms:  Discrete powdery white areas on lower leaf surfaces
 Chlorosis
Hosts:
  Oak, red maple
Cause:   Iron or manganese deficiency, often induced by high soil pH
Signs/Symptoms:  Yellow leaves with dark green veins
For more information see:  Chlorosis
 Scorch
Hosts:  Most deciduous trees
Cause:   Water stress induced by drought, high soil salt content, or other water-limiting factors
Signs/Symptoms:  Dead tissue on leaf margins
 Tatters
Hosts:
  Most deciduous trees, but commonly oak
Cause:  Possible early season cold injury
Signs/Symptoms:  Lacy, tattered-looking leaves
For more information see:  Tatters

For more information on deciduous tree leaf diseases: 

See https://pddc.wisc.edu/ or contact the University of Wisconsin Plant Disease Diagnostics Clinic (PDDC) at (608) 262-2863 or pddc@wisc.edu.

Authors:  Brian Hudelson, UW-Madison Plant Pathology
Last Revised:  02/29/2024
D-number:  D0041

Thanks to Jane Anklam, Mark Kopecky and Judy Reith – Rozelle for reviewing this document.

A complete inventory of UW Plant Disease Facts is available at the University of Wisconsin-Madison Plant Disease Diagnostics Clinic website: https://pddc.wisc.edu.

 

Send a Plant Sample for Analysis

Be cautious when self-diagnosing plant health issues. Very few diseases can accurately be diagnosed by eye.

Contact the UW Plant Disease Diagnostics Clinic (PDDC), and for a small fee, clinic staff can examine a plant, determine the cause of the disease/disorder, and provide advice on how to control or prevent the issue.

 


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