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Identifying and managing Christmas tree diseases, pests and other problems PNW659
- NE Christmas Tree Pest Manual (PDF)
- National Pesticide Information Center-NPIC
- Environmental Protection Agency-EPA
- Occupational Safety and Health Administration-OSHA
- Degree Day Model-Douglas-Fir Needle Midge
- Weeds of the West
- Growing degree day model for insect pests
- Washington State University Christmas tree program disease management resources