What is silver leaf? Silver leaf is a fungal disease that affects a wide range of deciduous trees. The disease has its biggest impact in fruit trees such as apple, pear and cherry, but can also affect ornamental trees such as willow, poplar, maple, oak, and elm. Silver leaf has traditionally been considered a disease […]
Red star rust (also known as Japanese apple rust or lipstick rust) is a type of Gymnosporangium rust. This plant disease is particularly concerning because of its potential negative impact in commercial apple production.
What is blister canker? Blister canker (also known as nailhead canker) is a potentially lethal disease that primarily affects apple and crabapple trees. Other trees and shrubs grown in Wisconsin that can be affected by the disease include American elm, honey locust, hornbeam, magnolia, mountain-ash (rowan), oak, pear, and serviceberry. What does blister canker look […]
What is Thyronectria canker? Thyronectria canker is a common fungal disease of honeylocust (Gleditsia triacanthos), occurring wherever this tree is grown. Black locust (Robinia pseudoacacia) and Kentucky coffeetree (Gymnocladus dioicus) have also been reported to be susceptible to the disease. Thyronectria canker is non-lethal and typically causes relatively minor damage to affected trees. What does […]
Learn about tree decline and dieback symptoms and how to prevent and treat problems that occur in this publication
This factsheet will help with the identification of some common leaf diseases of deciduous trees.
Gymnosporangium rusts, such as Cedar Apple Rust, need both junipers and woody plants in the rose family to complete their life cycle. Learn more in this factsheet.
Gray mold (or Botrytis blight) is a common and often serious fungal disease that can affect plants of all kinds. Learn more in this factsheet.
This fact sheet explores sun scald, girdling roots, mower injury, previous defoliation, graft incompatibility, twine and tree wrap injury, and gas leaks as common causes of tree decline and death.
Tar spot is a common, visually distinctive and primarily cosmetic fungal leaf spot disease that can affect many species of maple, including silver maple, sugar maple and Norway maple. Learn more in this factsheet.
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. Learn symptoms and more in this factsheet.
Armillaria root disease, also known as shoestring root rot, can affect most conifer and hardwood species, and is an often lethal disease of tree and shrub roots and lower stems. Learn more in this factsheet.
