Mealybugs

Karen Delahaut, formerly UW-Madison Fresh Market Vegetable Program Revised:  4/26/2004 Item number:  XHT1129 Mealybugs are slow-moving, small, oval insects that are covered with a white, cottony wax.  They are tropical insects that are typically only found on perennial foliage plants, and rarely on flowering or bedding plants.  They can infest all plant parts including the […]

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 […]

Four-Lined Plant Bug

Carla Staab*, Milwaukee Area Technical College, and Phil Pellitteri, UW Insect Diagnostic Lab ompleted as partial fulfillment of the requirements for an associate degree in Horticulture at the Milwaukee Area Technical College. Revised:  4/27/2004 Item number:  XHT1101 The adult four-lined plant bug (Poecalocapsus linectus) is a 1∕2 inch long, yellowish to yellowish-green true bug with […]

Pear Slug (Pear Sawfly)

Phil Pellitteri, UW Insect Diagnostic Lab Revised:  12/30/2010 Item number:  XHT1200 Pear slugs are not true slugs (see University of Wisconsin Garden Facts XHT1040), but are larvae of the pear sawfly (Calora cerasi). These larvae feed and cause damage on many kinds of ornamentals and fruit trees, including cherry, cotoneaster, mountain-ash, pear, purple leaf plum […]

Cicadas

R. Chris Williamson, UW-Extension Turf and Ornamental Specialist Revised:  8/13/2012 Item number:  XHT1068 Adult periodical cicadas (Magicicada spp.) are black and have reddish-orange eyes and legs, and have clear wings with orange veins that are positioned over their bodies like a roof or canopy.  Male cicadas typically make a loud buzzing noise or squawk when […]

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 […]

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