Lesson 4 — Key Diseases: ID & Conditions

Goal: understand the conditions that cause outbreaks so you fix the cause, not just symptoms.

Common nursery diseases

• Botrytis (gray mold) — thrives in cool, wet, still air
• Powdery mildew — thrives with humid canopy + low airflow
• Root rots (Pythium/Phytophthora) — wet media + low oxygen
• Leaf spots — splash + crowding

Conditions checklist

• Overwatering / slow drainage
• Overcrowding / no airflow
• Stagnant corners
• Infected incoming stock