Gadenin日本語Get the appCheck these first
- Does it rub off with a finger? Powder that rubs off is a fungus; marks that stay are scarring from pests.
- Is it on the upper or lower leaf surface, or concentrated on new shoots and leaf joints?
- If it is cottony, look inside the fluff for insects.
Most likely causes
From the pests and diseases recorded for this plant, the ones whose symptoms match, most serious first. Symptoms alone rarely confirm a cause, so use the linked page to check the signs and treatment.
Lace Bugs
The upper leaf surface bleaches into a whitish stipple, while black tar-like droppings and the insects themselves cover the underside. As it advances the whole plant looks whitish and growth declines.
How to identify and treat: Lace BugsPowdery Mildew
White patches appear scattered on the upper leaf surface at first, then the whole leaf is coated in a white powder. Leaves later yellow, brown and die back, and reduced photosynthesis cuts growth and yield.
How to identify and treat: Powdery MildewSpider Mites
Fine white stippling spreads across the upper leaf surface, and the leaf eventually whitens and dies back. In heavy infestations fine webbing appears on leaf undersides and shoot tips.
How to identify and treat: Spider MitesOther possible causes
The three above are the causes on record for this symptom.
Other symptoms on this plant
What other growers did about it
A page like this one can tell you what azalea white powder on leaves is and what to try. What it cannot tell you is what actually happened to someone who had it on the same plant, at the same point in the season, and what they did next.
Gadenin is a free garden journal built around that. You photograph the plant, tag what you are seeing, and the entries line up by date for each plant you grow.
- Tag the problem and the app tells you how many other growers have logged the same thing on the same plant.
- Growers who make their records public can be followed, so you can read what they did and how it turned out.
- Next season your own entries come back at the same point in the year, so you check the plant before it starts.
Free on iPhone. Recording, tagging and reading public records cost nothing.