nurtomiRaised bumps or blisters
Edema is a physical response to a water imbalance.
What to look for
Look for small raised blisters or corky bumps, often on the underside of a leaf. They can resemble scale insects or spots, so inspect closely for actual insects and consider recent watering conditions.
What to do
Let the mix dry to the level appropriate for the plant between waterings and make sure the pot drains. Existing marks may remain; compare new leaves rather than treating every bump as a pest.