Helpful Links

www.isa-arbor.com - International Society of Arboriculture; arboricultural information.

www.csrees.usda.gov/qlinks/partners/state_partners.html - find the nearest State University affiliated cooperative extension service to help you diagnose a specific tree/shrub problem in your area.

www.extension.psu.edu - Penn State Cooperative Extension

sepaipm.cas.psu.edu - Southeastern Pennsylvania IPM Research Group