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.
Iron Deficiency
Yellow-white interveinal chlorosis begins on the new leaves with only the veins staying green. In severe cases the new leaves bleach entirely white and growth stops.
How to identify and treat: Iron DeficiencyNettle Caterpillars
From summer into autumn they cluster on leaf undersides and graze the tissue so the leaves turn translucent white. Larger larvae riddle the leaves with holes and strip the branches bare.
General description; not specific to this plant.
How to identify and treat: Nettle CaterpillarsMealybugs
White cottony masses appear at leaf axils, on fruit clusters and at the edge of the potting soil. Sap feeding weakens growth and the honeydew leads to sooty mold.
General description; not specific to this plant.
How to identify and treat: MealybugsOther possible causes
- Powdery Mildew — White patches appear scattered on the upper leaf surface at first, then the whole leaf is …
- Sclerotinia Rot — The crown, stem or head rots in a water-soaked way and is covered in white cottony myceliu…
- Leaf Spot — Small round brown to gray-white lesions appear on the lower leaves, the centers turning gr…
Other symptoms on this plant
What other growers did about it
A page like this one can tell you what blueberry 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.