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Helianthus annuus
Growing calendar
Typical timing for central Japan (Kanto region). Shift it for your own climate, and record your actual dates.
Guides
- Types of Sunflower: Single-Stem Giants and Branching Multi-Headed Kinds
- How to Sow Sunflower Seed: Depth, Spacing and Soil Temperature
- Sunflower Care: Staking Tall Stems Before They Lean
- What to Watch on a Sunflower: Reading Leaves, Stem and Head
- Harvesting Sunflower Seeds: When to Cut the Head and How to Dry It
- Sunflower Growing Calendar: Sowing, Staking, Flowering and Seed
Common problems
Start from what you can see on the plant.
Pests and diseases (25)
Problems recorded for this plant, most serious first.
Aphids
MajorPest
Small green or black insects cluster on shoot tips and leaf undersides, crinkling the leaves and stopping growth. The honeydew they excrete supports sooty mold that blackens the foliage.
Powdery Mildew
MajorDisease
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.
Sclerotinia Rot
MajorDisease
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.
Damping-off
CommonDisease
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.
Downy Mildew
CommonDisease
Pale yellow to yellow-brown angular lesions form on the upper leaf surface with a gray-purple mold in the matching spot underneath. Lesions merge, the leaves die back and the plant declines early.
Cabbage Armyworm
CommonPest
Young larvae feed in groups on the leaf underside, eating only the tissue so the leaf turns translucent white. Larger larvae chew big holes and can strip a plant bare in a single night.
Bacterial Wilt
Disease
Leaves wilt while still green during the day and recover in the morning and evening; after a few days of this the plant dies. Cut the stem and stand it in water and a milky white bacterial ooze streams out in threads.
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.
Brown Leaf Spot
Disease
Small light brown to gray-brown spots form on the leaves and enlarge into irregular lesions. When they merge the whole leaf dies and plant vigor drops sharply.
Crown Gall
Disease
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.
Rust
Disease
Small raised orange-yellow to red-brown pustules form on both leaf surfaces, then rupture and release powdery spores. Heavy infection yellows the leaves and kills them early.
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.
Root Rot
Disease
Fine roots rot brown to blackish brown, growth stops and the lower leaves yellow. The plant wilts easily in the daytime and eventually dies outright.
Root-knot Nematode
Pest
The plant wilts in the daytime and does not recover with feeding or watering. Pull it up and the roots carry beaded chains of galls of varying size with few fine roots.
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.
Verticillium Wilt
Disease
Only one side of the lower leaves yellows and wilts, and the symptom moves up the plant. Stem vascular tissue turns pale brown and the plant dies without ever growing well.
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.
Leaf Spot
Disease
Small round brown to gray-white lesions appear on the lower leaves, the centers turning gray with tiny black specks. As they multiply the leaf yellows and drops early.
Ring Rot
Disease
The bark of branches and trunk becomes rough and warty, serving as the inoculum source. Fruit develops round brown lesions that soften and rot in concentric rings.
