Deciduous Tree Leaf Disease Quick Reference | Plant Disease Diagnostics Clinic

UW Plant Disease Facts

Authors: Brian Hudelson, UW-Madison Plant Pathology

Last Revised: 04/09/26

D-number: D0041

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: UW Plant Disease Facts D0002

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: UW Plant Disease Facts D0089

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: UW Plant Disease Facts D0118

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: UW Plant Disease Facts D0004

Gymnosporangium Rusts

Hosts: Apple, crabapple, hawthorn
Pathogens: Gymnosporangium spp.
Signs/Symptoms: Bright yellow-orange, circular leaf spots
For more information see: UW Plant Disease Facts D0058

Powdery 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: UW Plant Disease Facts D0087

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: UW Plant Disease Facts D0030

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: UW Plant Disease Facts D0111

For more information on deciduous tree leaf diseases:

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

This Fact Sheet is also available in PDF format:

Full Color PDF

An EEO/Affirmative Action employer, University of Wisconsin-Madison Division of Extension provides equal opportunities in employment and programming, including Title IX and ADA requirements. This document can be provided in an alternative format by calling Brian Hudelson at 608-262-2863 (711 for Wisconsin Relay).

Thanks to Diana Alfuth, Kristin Krokowski, and Patti Nagai for reviewing this document, and to Matt Hanson for supplying the powdery mildew photo

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)

Submit additional lawn, landscape, and gardening questions at the Ask a Gardening Question page (https://hort.extension.wisc.edu/ask-a-gardening-question/) of the University of Wisconsin-Madison Division of Extension Horticulture website.