Check these first
- Are the stems stretched with long gaps between leaves? That is a lack of light.
- Are new leaves curled, twisted, or unusually small? Think virus or sap-sucking pests.
- Are the leaves dark and lush but there are no flowers or fruit? That is too much nitrogen.
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.
Mealybugs
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: MealybugsIron 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.
General description; not specific to this plant.
How to identify and treat: Iron DeficiencyCitrus Leafminer
Silvery winding mines run through newly expanded young leaves, which crinkle and roll inward, with a translucent larva at the head of the mine. It does not attack hardened spring leaves and concentrates on shoots growing…
How to identify and treat: Citrus LeafminerOther possible causes
- Crown Gall — Irregular galls form at the crown and on the roots, gradually enlarging and turning woody.…
Other symptoms on this plant
What other growers did about it
A page like this one can tell you what kumquat not growing well 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.