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Citrus sinensis
Growing calendar
Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.
Guides
- Planting an Orange Tree: Site, Depth and Keeping the Graft Clear
- Pruning an Orange Tree: When to Cut, What to Take Out, What to Leave
- Orange Tree Care: Watering, Feeding, Mulch and Removing Suckers
- Orange Tree Growing Calendar: A Year Around a Long-Hanging Crop
- Orange Tree Pests and Problems: Scale, Sooty Mold, Leaf Miner and Split Fruit
- When to Pick Oranges: Ripeness Tests, Green Skin and Leaving Fruit Too Long
Common problems
Start from what you can see on the plant.
Pests and diseases (121)
Problems recorded for this plant, most serious first.
Scale Insects
MajorPest
Small white or brown shell-like insects dot the shoots and leaves. The plant loses vigor and honeydew-fed sooty mold blackens the shoots and foliage.
Longhorn Beetles
MajorPest
Sawdust-like frass is pushed out at the trunk base or branch crotches. The wood is hollowed out, the tree loses vigor, and the trunk may snap in strong wind.
Citrus Melanose
MajorDisease
Tiny dark brown specks are scattered over fruit and leaves, sometimes clustering into tear-streaks or a sandpaper texture. Heavy infection makes the rind rough and badly cuts appearance value.
Sooty Mold
MajorDisease
A thin black sooty mold spreads over the upper leaf surface, shoots and fruit. It does not invade the tissue itself, but it blocks photosynthesis and badly spoils appearance.
Mealybugs
CommonPest
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.
Iron Deficiency
CommonDisorder
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.
Leafrollers
CommonPest
Leaves are webbed into tubes or folded in half, with a green or brown caterpillar inside. Shoot tips and fruit surfaces are also gnawed, disrupting growth.
Stink Bugs
OccasionalPest
Small feeding punctures on fruit become sunken or turn spongy and discolored. On legumes the pods fail to fill, and fruit drop and deformity increase.
Crown Gall
OccasionalDisease
Irregular galls form at the crown and on the roots, gradually enlarging and turning woody. They block the flow of water and nutrients, so the plant loses vigor and may die.
Fruit Borers
OccasionalPest
Small entry holes with gummy exudate and frass appear on the fruit surface. On new shoots the tips wilt and die back and the inside is hollowed out.
Bagworms
OccasionalPest
Bag-shaped cases covered in twigs and leaf fragments hang from the branches. Leaves are eaten irregularly and heavy infestation leaves the branch tips bare.
Powdery Mildew
Disease
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.
Late Blight
Disease
Dark green water-soaked lesions appear on the leaves and expand quickly into brown dead tissue. White mold forms on the underside and at the lesion edge, and dark brown lesions spread to stems and fruit.
Bacterial Canker
Disease
Leaf margins scorch and die back, and splitting the stem reveals browned vascular tissue. Scabby, bird's-eye lesions form on fruit and shoots.
Sclerotinia Rot
Disease
The crown, stem or head rots in a water-soaked way and is covered in white cottony mycelium. Black sclerotia later form inside and on the surface, and the plant wilts and dies.
Black Rot
Disease
V-shaped yellowing spreads inward from the leaf margins and the veins darken into a black network. As it advances the whole plant wilts and dies.
Black Spot
Disease
On roses, dark brown lesions with radiating edges form on the leaves, which yellow around them and drop. On pear, sooty black lesions appear on leaves, fruit and the calyx of young fruit, deforming the fruit.
Southern Blight
Disease
The stem rots at soil level and white silky mycelium spreads over the crown and the surrounding soil surface. Brown sclerotia the size of rapeseed then form and the plant wilts and dies rapidly.
Anthracnose
Disease
Light brown to dark brown round lesions with sharp margins form on leaves and fruit, slightly sunken in the center. In wet weather salmon-pink slimy spore masses ooze out on the lesions.
Damping-off
Disease
The stem pinches in at soil level, turning water-soaked to brown and thin, and the seedling topples over. Infection before emergence makes the stand uneven with missing plants.
Root-lesion Nematode
Pest
Elongated blackish brown necrotic lesions form on the root surface and fine roots rot away. Above ground the stand is uneven and plants stay small with pale foliage.
Gray Mold
Disease
Water-soaked brown lesions form on flowers, fruit and leaves, densely covered by a fuzzy gray mold. Fruit rots and drops, and decay continues in storage after harvest.
Bacterial Spot
Disease
Small water-soaked spots appear on the leaves, later turning brown with yellowing around them. Fruit develops water-soaked or scabby spots from which rot spreads.
