UW Plant Disease Facts

Deciduous Tree Leaf Disease Quick Reference

Authors: Brian Hudelson, UW-Madison Plant Pathology
Last Revised: 04/09/2009
D-number: XHT1190
Anthracnose for Quick Guide 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 Garden Facts XHT1001a/b/c
Purple-bordered leaf spot 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 Garden Facts XHT1149
 Tubakia 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: UW Garden Facts XHT1104
 Scab Scab Hosts: Apple, crabapple, pear, mountain-ash Pathogen: Venturia inaequalis Signs/Symptoms: Circular, black leaf spots with feathery edges; eventual leaf loss For more information see: UW Garden Facts XHT1007a/b
 Cedar-Apple Rust Cedar-Apple Rust Hosts: Apple, crabapple, hawthorn Pathogens: Gymnosporangium spp. Signs/Symptoms: Bright yellow-orange, circular leaf spots For more information see: UW Garden Facts XHT1009a/b
 Powdery Mildew 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 Garden Facts XHT1005
 Downy Leaf Spot Downy Leaf Spot Hosts: Hickory, walnut Pathogen: Microstroma juglandis Signs/Symptoms: Discrete powdery white areas on lower leaf surfaces
 Clorosis 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 Garden Facts XHT1002
 Scorch 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 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 Garden Facts XHT1141

For more information on deciduous tree leaf diseases: See University of Wisconsin Garden Facts XHT1001a/b/c, XHT1002, XHT1005, XHT1007a/b, XHT1009a/b, XHT1104, XHT1141, and XHT1149, or contact your County Extension agent.

This Fact Sheet is also available in PDF format:

© 2009 the Board of Regents of the University of Wisconsin System doing business as University of Wisconsin-Madison Division of Extension.

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.