Magnolia Scale

Phil Pellitteri, UW Insect Diagnostic Lab, UW-Extension Revised:  8/6/2012 Item number:  XHT1154 Magnolia scale has become an increasingly common problem on magnolia trees in Wisconsin.  Popular magnolia species such as star magnolia (Magnolia stellata) and saucer magnolia (Magnolia x soulangiana) are very susceptible to this insect. Appearance: Adult magnolia scale females are shiny brown, elliptical […]

Guignardia Leaf Spot

Brian Hudelson, UW-Madison Plant Pathology, UW-Extension Revised:  4/28/2012 Item number:  XHT1123 What is Guignardia leaf spot?  Guignardia leaf spot is a common fungal leaf spot that affects vining plants such as Boston ivy and Virginia-creeper.  The pathogen that causes Guignardia leaf spot also causes a leaf spot and fruit rot of grape called black rot. […]

Golden Canker (Cryptodiaporthe Canker)

Brian Hudelson, UW-Madison Plant Pathology, UW-Extension Revised:  8/6/2012 Item number:  XHT1125 What is golden canker? Golden canker (officially Cryptodiaporthe canker) is a visually distinct and increasingly common disease of alternate-leafed dogwoods such as pagoda dogwood. This disease can potentially be lethal if infections occur on the main trunk of a tree. What does golden canker […]

Euonymus Scale

Phil Pellitteri, UW Insect Diagnostic Lab, UW-Extension Revised:  8/6/2012 Item number:  XHT1153 Euonymus scale is a non-native scale that attacks evergreen shrub and vine forms of Euonymus (e.g., wintercreeper).  In addition, this insect attacks privet, bittersweet and pachysandra. Appearance: Euonymus scale females grow up to 1/16 inch in length, are brown and are shaped like […]

Dutch Elm Disease

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:  XHT1076 What is Dutch elm disease? Dutch elm disease is a lethal fungal disease of native North American elms.  The fungi that cause Dutch […]

Boxelder Bugs

Rebecca Hoffman*, UW-Entomology and Phil Pellitteri, UW Insect Diagnostic Lab Revised:  5/7/2010 Item number:  XHT1100 Boxelder bugs, a true bug from the insect family Rhopalidae, are commonly found both outside and inside homes during the fall through early spring. Boxelder bugs are about 3⁄4 of an inch long, and black in color with three red […]

Black Walnut Toxicity

Ann Joy and Brian Hudelson, UW-Madison Plant Pathology Revised:  5/7/2010 Item number:  XHT1017 What is black walnut toxicity? Black walnut trees (Juglans nigra) produce a toxic substance (called juglone) that prevents many plants from growing under or near them. Related trees like butternut (J. cinerea) and shagbark hickory (Carya ovata) also produce juglone, but in […]

Ash Flower Gall

Phil Pellitteri, UW Insect Diagnostic Lab, UW-Extension Revised:  8/6/2012 Item number:  XHT1048 What is wrong with my ash tree?  Galls are abnormal plant growth that can be caused by insects, mites or plant diseases.  On ash trees, a tiny eriophyid mite causes male flowers to grow into round greenish, 1∕2 to 1 inch diameter tumor-like […]

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 […]

Ash Yellows

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:  XHT1079 What is ash yellows?  Ash yellows is a chronic, systemic disease that affects ash trees of all ages.  White ash is particularly susceptible […]

Black Knot

Brian Hudelson, UW-Madison Plant Pathology, UW-Extension Revised:  5/1/2010 Item number:  XHT1056 What is black knot?  Black knot is a disfiguring and potentially lethal disease of trees and shrubs in the genus Prunus.  This genus includes stone fruits such as wild, fruit-bearing and ornamental plums and cherries. What does black knot look like?  During the first […]

Controlling Carpenter Ants

P.J. Pellitteri Revised:  1/15/2003 Item number: A3641 (Download Now) If you see large black ants skittering around your home, they may be carpenter ants. This helpful publication will help you identify and control these household pests.     Download Article

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