Diagnosing plant problems

Questions to ask in diagnosing problems

1. Does a real problem exist with the plant?
2. What is the population of the plants?
3. How many of the plants are affected?
4. What is the pattern of damage in the population? Do the cultural conditions of the affected plants differ from those of the unaffected plants?
5. What part (or parts) of the plant is (are) affected?
6. What is the pattern of damage within the plant?
7. What is the pattern of damage on the plant part?
8. When did the symptoms appear?
9. Are the symptoms spreading, improving or constant?
10. Are there any signs of a pest present?

Resources

OSU Extension

• OSU Extension Publications: OSU gardening publications
• OSU Extension Gardening: Browse these topiics for helpful articles, videos and more!

Plant Identification

• OSU plant identification website

Plant Diseases

• Pacific Northwest Plant Disease Management Handbook

Insect Pests

• Pacific Northwest Insect Management Handbook

General pest or IPM

• Oregon IPM Center
• University of California Integrated Pest Management
• WSU Pest leaflet series
• USDA Forest Service Pacific Northwest Region Forest Health Protection

Plant Problem Diagnosis

• Washington State University Hortsense
• University of Minnesota Extension Diagnose a problem
• Plant pathology diagnostic laboratory at OSU

Pesticide information

• National Pesticide Information Center (NPIC)