Southern Blight

Authors: Ann Joy and Brian Hudelson, UW-Madison Plant Pathology Last Revised: 01/03/2019 X-number: XHT1042   What is Southern blight?  Southern blight is a lethal fungal disease that is most common in the tropics and subtropics.  This disease causes damage in the southern U.S. and can even cause problems in temperate locations like Wisconsin during periods of warm, moist […]

Plum Pox

Patricia McManus, UW-Madison Department of Plant Pathology Revised:  5/20/2011 Item number:  XHT1028 What is plum pox? Plum pox, also known as “sharka,” is a virus disease that affects stone fruits including plums, peaches, nectarines, apricots, and ornamental Prunus species.  Cherries are resistant to most strains of plum pox, or at least do not show symptoms.  […]

Crown Gall

Ann Joy and Brian Hudelson, UW-Madison Plant Pathology Revised:  5/5/2005 Item number:  XHT1037 What is a crown gall?  Crown gall is the most widely distributed bacterial disease of plants in the world, affecting over 100 species of fruit crops, and woody and herbaceous ornamentals, including rose, euonymus, lilac, poplar, viburnum, willow, apple, pear, brambles, stone […]

Dead Man’s Fingers

Ann Joy and Brian Hudelson, UW-Madison Plant Pathology Revised:  8/13/2012 Item number:  XHT1201 What is dead man’s fingers?  Dead man’s fingers is the name of a mushroom-like fungal growth that can be found at the base of dead or dying trees and shrubs, as well as wood objects (e.g., wood barrels) that are in contact […]

Bitter Pit and Cork Spot

Teryl Roper, UW-Madison, Dept of Horticulture Revised:  4/24/2004 Item number:  XHT1055 Bitter pit and cork spot are common disorders of Wisconsin apples. These two disorders don’t occur every year, but when weather conditions are just right (or just wrong, depending on your perspective) they can be major problems. This fact sheet describes the causes of […]

Bacterial Canker

Mary Francis Heimann, O.S.F., Distinguished Outreach Specialist emerita at the University of Wisconsin-Madison and Brian Hudelson, UW-Madison Plant Pathology Revised:  12/9/2004 Item number:  XHT1026 What is bacterial canker?  Bacterial canker is a common and sometimes lethal disease of trees in the genus Prunus including cherry, plum and peach.  Bacterial canker is also known as “gummosis”, […]

Peach Leaf Curl

Authors: Patricia McManus and Brian Hudelson, UW-Madison Plant Pathology Last Revised: 04/06/2021 X-number: XHT1069 What is peach leaf curl? Peach leaf curl is a common disease of peach and nectarine trees throughout the Midwest and eastern U.S. Where the disease is severe, tree vigor and fruit quality and yield are reduced. Peach leaf curl often […]

Fire Blight

Ann Joy and Brian Hudelson, UW-Madison Plant Pathology Revised:  4/24/2004 Item number:  XHT1090 What is fire blight?  Fire blight is the most destructive bacterial disease affecting plants in the rose family, including apple, pear, crabapple, hawthorn, cotoneaster, mountain ash, quince, rose, pyracantha, and spirea.  It can kill or disfigure a tree or shrub, depending on […]

Downy Mildew

Jim Olis* and Brian Hudelson, UW-Madison Plant Pathology *Completed as partial fulfillment of the requirements for a BS in Plant Pathology at the University of Wisconsin Madison. Revised:  8/6/2012 Item number:  XHT1077 What is downy mildew? The downy mildews are a group of fungal diseases that cause destruction of the leaves, stems, flowers and fruits […]

Apple Scab

Brian Hudelson, UW-Madison Plant Pathology Revised:  11/19/2018 Item number:  XHT1007 What is apple scab?  Apple scab is a potentially serious fungal disease of ornamental and fruit trees in the rose family.  Trees that are most commonly and severely affected include crabapple, hawthorn, mountain-ash, apple and pear.  In ornamental trees, leaf loss caused by apple scab […]

Root and Crown Rots

Brian Hudelson, UW-Madison Plant Pathology and Laura Jull, UW-Madison Horticulture Revised:  8/13/2012 Item number:  XHT1070 What is root/crown rot? Root/crown rot is a general term that describes any disease of woody ornamentals where the pathogen (causal organism) attacks and leads to the deterioration of a plant’s root system and/or lower trunk or branches near the […]

Bacterial Blight

Gina Foreman* and Brian Hudelson, UW-Madison Plant Pathology *Completed as partial fulfillment of the requirements for Plant Pathology 875 – Plant Disease Diagnostics Clinic Internship at the University of Wisconsin Madison. Revised:  4/25/2004 Item number:  XHT1093 What is bacterial blight?  Bacterial blight, also known as blossom blight or shoot blight, is a common and often […]

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