Emerald Ash Borer
Banded Elm Bark Beetle
The Banded Elm Bark Beetle has been detected in Michigan.
Blue Spruce Diseases
Colorado blue spruce is a popular tree species planted for windbreaks, screens and general landscape purposes. Unfortunately, blue spruce is susceptible to several diseases and insect pests. To learn more about these diseases and how to control them view the Spruce Problems handout compiled by the WCCD.
Diplodia Tip Blight
The fungus, Sphaeropsis sapinea (also known as Diplodia pinea) can cause serious damage to Austrian, ponderosa, red, Scots, mugo, jack, and white pine.
Eastern Tent Caterpillar (Malicosoma americanum)
The eastern tent caterpillar may be found on fruit trees like apple, chokecherry, crabapple, plum and cherry in May and June. Larvae feed on leaves and make a noticeable web or ‘tent’ in the branches. However, these caterpillars generally do not affect tree health.
Emerald Ash Borer
European Pine Sawfly
This sawfly can severely defoliate jack, red & Scotch pine primarily, but will feed on other pines as well. Here is more information:
Forest Tent Caterpillar
The forest tent caterpillar is a native species found throughout hardwood forests of North America. It feeds on the leaves of many trees, but in Michigan outbreaks occur in aspen, birch, basswood, sugar maple and oak stands. More information is available here:
Gypsy Moth
The gypsy moth has been a primary defoliator of hardwoods in the Northeastern United States since its introduction in 1869. For additional information, follow these links:
Hemlock Woolly Adelgid
The Hemlock Woolly Adelgid has been discovered in several Michigan locations and the Department of Agriculture and Rural Development has instituted a quarantine related to this pest.
Oak Wilt
This is an aggressive disease that affects many species of oak. It is one of the most serious tree diseases in the eastern United States, killing thousands of oaks each year in forests, woodlots, and home landscapes. Learn more about Oak Wilt at:
Sirex Woodwasp
This insect attacks Scotch and Austrian pines almost exclusively. More information is available at:
Spruce Decline, Diseases & Pests
Spruce trees are experiencing decline throughout Michigan from a variety of maladies—including several needle cast and canker diseases; gall aphids and spider mites. To learn more about what may be affecting your spruce trees, view the Spruce Problems handout prepared by the Conservation District.
Thousand Cankers Disease
This disease has the potential in impact black walnut trees in Michigan.
White Pine Shoot Borer (Eastern Pineshoot Borer)
Other Insect & Disease information
The Banded Elm Bark Beetle has been detected in Michigan.
- Banded Elm Bark Beetle (USDA Forest Service, Pest Alert, 2006)
Blue Spruce Diseases
Colorado blue spruce is a popular tree species planted for windbreaks, screens and general landscape purposes. Unfortunately, blue spruce is susceptible to several diseases and insect pests. To learn more about these diseases and how to control them view the Spruce Problems handout compiled by the WCCD.
Diplodia Tip Blight
The fungus, Sphaeropsis sapinea (also known as Diplodia pinea) can cause serious damage to Austrian, ponderosa, red, Scots, mugo, jack, and white pine.
- Diplodia (Sphaeropsis) Tip Blight (PennState Extension, 2017)
- Diplodia Tip Blight (Cornell University, Plant Disease Diagnostic Clinic, 2015)
Eastern Tent Caterpillar (Malicosoma americanum)
The eastern tent caterpillar may be found on fruit trees like apple, chokecherry, crabapple, plum and cherry in May and June. Larvae feed on leaves and make a noticeable web or ‘tent’ in the branches. However, these caterpillars generally do not affect tree health.
- Eastern Tent Caterpillars (University of Minnesota Extension, 2018)
- Eastern Tent Caterpillar (PennState Extension, 2002)
- Eastern Tent Caterpillar (MSU, Integrated Pest Management, 2015)
Emerald Ash Borer
- Guidelines for effectively using insecticides to manage EAB are described in Insecticide Options for Protecting Ash Trees From Emerald Ash Borer (May 2009)
- My Ash Tree is Dead, Now What Do I Do? (MSU Extension, 2007)
- Emerald Ash Borer and Your Woodland (MSU Extension, 2005)
- EAB web site, Michigan Department of Agriculture & Rural Development
- EAB Cost Calculator - Compare costs of various removal and treatment scenarios (Purdue University)
European Pine Sawfly
This sawfly can severely defoliate jack, red & Scotch pine primarily, but will feed on other pines as well. Here is more information:
- European Pine Sawfly (USDA Forest Service, 1971)
Forest Tent Caterpillar
The forest tent caterpillar is a native species found throughout hardwood forests of North America. It feeds on the leaves of many trees, but in Michigan outbreaks occur in aspen, birch, basswood, sugar maple and oak stands. More information is available here:
- Forest Tent Caterpillar in the Upper Midwest (USDA Forest Service, Northeastern Area)
- Forest Tent Caterpillar (USDA Forest Service, Forest Insect & Disease Leaflet 9)
Gypsy Moth
The gypsy moth has been a primary defoliator of hardwoods in the Northeastern United States since its introduction in 1869. For additional information, follow these links:
- Gypsy Moth (USDA Forest Service, Northeastern Area)
- Gypsy Moth (USDA Forest Service, Forest Insect & Disease Leaflet 162)
Hemlock Woolly Adelgid
The Hemlock Woolly Adelgid has been discovered in several Michigan locations and the Department of Agriculture and Rural Development has instituted a quarantine related to this pest.
- Exotic Hemlock-Killing Insect Found in Three Michigan Counties (Michigan DARD, November 12, 2010 )
- Forest Health Protection—Hemlock Woolly Adelgid (USDA Forest Service)
Oak Wilt
This is an aggressive disease that affects many species of oak. It is one of the most serious tree diseases in the eastern United States, killing thousands of oaks each year in forests, woodlots, and home landscapes. Learn more about Oak Wilt at:
- Forest Health Protection—Oak Wilt (USDA Forest Service Northeastern Area)
- Oak Wilt (USDA Forest Service, Forest Insect & Disease Leaflet 29)
Sirex Woodwasp
This insect attacks Scotch and Austrian pines almost exclusively. More information is available at:
- Sirex woodwasp—Sirex noctilio F. (Hymenoptera: Siricidae) (USDA Forest Service, Northeastern Area, 2005)
- Sirex noctilio (Sirex Woodwasp) (USDA Animal and Plant Health Inspection Service)
Spruce Decline, Diseases & Pests
Spruce trees are experiencing decline throughout Michigan from a variety of maladies—including several needle cast and canker diseases; gall aphids and spider mites. To learn more about what may be affecting your spruce trees, view the Spruce Problems handout prepared by the Conservation District.
Thousand Cankers Disease
This disease has the potential in impact black walnut trees in Michigan.
- Thousand Cankers Black Walnut Disease
- Thousand Cankers Disease (USDA Forest Service, Pest Alert, 2011)
White Pine Shoot Borer (Eastern Pineshoot Borer)
- Eastern Pineshoot Borer(USDA Forest Service, Forest Insect & Disease Leaflet 134)
Other Insect & Disease information
- Forest Pests(Michigan DNR, Michigan Forest Health News, August 2011)
- Directory of Exotic Forest Insects and Disease Pests(MSU Extension, June 2002)
