Monitoring Sudden Oak Death
- Created by the University of California's Sudden Oak Death Research Team, this site monitors the distribution of the disease.
- http://kellylab.berkeley.edu/SODmonitoring/

Exotic Forest Pest Information System for North America
- Database containing information on exotic insects, mites and pathogens with potential to cause significant damage to North American forest resources.
- http://spfnic.fs.fed.us/exfor/

Plant disease diagnostics (Minnesota)
- Plant disease diagnostics by the University of Minnesota Extension Service. Mainly designed for plant disease problems in yards and gardens. It is based on visual observations of symptoms. It has a section on trees that might be useful in forestry.
- http://www.extension.umn.edu/projects/yardandgarden/diagnostics/

Invasive and Exotic Species of North America
- Provides extensive information on all kinds of invasive species in North America.
- http://www.invasivespecies.gov/

Gypsy Moth in North America
- Extensive information on the biology, impact, distribution and management of this exotic insect in North America.
- http://www.fs.fed.us/ne/morgantown/4557/gmoth/

Insects and Diseases of Eastern Canada's Forests
- An extensive collection of images and a variety of information on the main insects and diseases of the forests of Quebec and Eastern Canada.
- http://www.cfl.scf.rncan.gc.ca/collections-cfl/home.html

USDA Forest Insect and Disease Leaflets
- USDA technical publications that address specific tree pests and diseases, including identification and control.
- http://www.na.fs.fed.us/spfo/pubs/fidlpage.htm

Forest and Shade Tree Pathology
- Online textbook, news and upcoming meetings of forest pathology.
- http://www.forestpathology.org/

California Oak Mortality Task Force
- Task force focusing on the pathogen causing Sudden Oak Death disease through research, management, education and public policy.
- http://www.cnr.berkeley.edu/comtf/

Forestry Images
- Quality photographs of forest insects and disease organisms. Contains image search or browse by categories.
- http://www.forestryimages.org/

Bugwood Network, The University of Georgia
- Extensive resource on forest insects and related topics.
- http://www.bugwood.org/

Asian Longhorned Beetle
- Brief account of the introduction of this Chinese insect into North America, and with a list of the affected species.
- http://www.asian-longhorned-beetle.com

Gypsy Moth
- A short account of this caterpillar pest of maples, oaks and elms.
- http://www.gypsy-moth.com

Focus on Woody Plant Diseases
- Information by host plant on diseases and damages affecting trees and perennial flowers from the University of Illinois Extension.
- http://www.urbanext.uiuc.edu/focus/

Tent Caterpillars
- The Eastern tent caterpillar affects black cherry trees and other fruit and shade trees. The forest tent caterpillar infests hardwood trees such as sugar maple and oak.
- http://www.tent-caterpillar.com

Brown Spruce Longhorn Beetle
- Brief account of this pest of spruce trees, its growth, and means of control.
- http://www.brown-spruce-longhorn-beetle.com

US Forestry Service Pest Alerts
- Collection of forest and tree health publications and fact sheets, primarily for midcontinent North America.
- http://www.fs.fed.us/na/morgantown/fhp/palerts/palerts.htm