Summer Flowering Trees, Shrubs and Vines

Laura Jull, UW-Madison Horticulture Revised:  8/13/2012 Item number:  XHT1016 May Showers Bring Summer Flowers: Most gardeners think that spring is the time of year when woody plants flower.  However, many trees and shrubs flower from late spring to late summer.  Wisconsin homeowners can choose from a variety of plants listed below to insure continual bloom […]

Spruce Spider Mite

Phil Pellitteri, UW Insect Diagnostic Lab, UW-Extension Revised:  8/13/2012 Item number:  XHT1109 Spruce spider mites can attack a number of conifers including spruce, hemlock, white cedar (arborvitae), larch, and juniper. These mites go through four to six generations per year and populations can explode under warm, dry conditions. Spider mites feed by sucking on plant […]

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 […]

Rhizosphaera Needle Cast

Rhizosphaera needle cast is the most common disease of Colorado blue spruce in Wisconsin. It makes Colorado blue spruce unsightly and unusable in many landscape settings. The disease can also affect other conifers including black, Engelmann, Serbian, Sitka, and white (e.g., Black Hills) spruce; Austrian, mugo and eastern white pine; Douglas-fir, balsam fir and western hemlock.

Tar Spot of Trees and Shrubs

Authors: Brian Hudelson, UW-Madison Plant Pathology Last Revised: 12/17/2018 X-number: XHT1126 What is tar spot?   Tar spot is a common, visually distinctive and primarily cosmetic fungal leaf spot disease.  Tar spot can affect many species of maple, including (but not limited to) silver maple, sugar maple and Norway maple.  Boxelder (also known as ash-leaved maple), willow, holly and […]

Purple Bordered Leaf Spot

Barrett Gruber*, Courtney E. Jahn*, Glen Stanosz and Brian Hudelson, UW-Madison Plant Pathology *Completed as partial fulfillment of the requirements for the graduate course: “Plant Pathology 559: Diseases of Economic Crops.” Revised:  8/13/2012 Item number:  XHT1149 What is purple-bordered leaf spot? Purple-bordered leaf spot (also called eye spot or Phyllosticta leaf spot) is a common, […]

Pine Root Collar Weevil

Vijai Pandian, UW-Extension Brown County and Phil Pellitteri, UW Insect Diagnostic Lab Revised:  8/13/2012 Item number:  XHT1183 Pine root collar weevil is a destructive pest of Austrian pine, Scots pine, red pine and more rarely Eastern white pine.  Young Austrian, Scots and red pines that are two to four inches in diameter at the soil […]

Phomopsis Tip 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:  8/13/2012 Item number:  XHT1099 What is Phomopsis tip blight? Phomopsis tip blight is one of the most common fungal diseases of conifers in […]

Oak Wilt

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:  8/13/2012 Item number:  XHT1075 What is oak wilt? Oak wilt is a lethal fungal disease that affects virtually all species of oaks.  Oaks in the red oak […]

Herbicide Damage

Brian Hudelson, UW-Madison Plant Pathology Revised:  5/11/2010 Item number:  XHT1004 What is herbicide damage?  Herbicide damage is any adverse, undesired effect on a plant that is caused by exposure of that plant to a pesticide designed for weed control (i.e., a herbicide).  Any plant can be subject to this problem.   What does herbicide damage […]

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 […]

Spongy Moth

P.J. Liesch, UW Entomology and R. Chris Williamson, formerly UW Entomology Revised:  4/1/2022 Item number:  XHT1063 The spongy moth, Lymantria dispar (formerly known as the “gypsy moth”) is native to parts of Europe, Asia, and North Africa. It was inadvertently introduced to North America in New England in 1869 and has since spread westward. Over […]

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