Large-flowered Tickseed with Southern Blight: Prevention & Cure

Coreopsis grandiflora

Susceptibility: Moderate Severity: High Difficulty: Easy

Southern Blight on Large-flowered Tickseed: What to Know?

Southern Blight on Large-flowered Tickseed (Coreopsis grandiflora) is a fungal condition with high severity. Large-flowered Tickseed has moderate susceptibility to this disease. Southern blight is a devastating soilborne fungal disease caused by Athelia rolfsii (formerly Sclerotium rolfsii), affecting over 500 plant species including vegetables, ornamentals, and fruit crops....

Large-flowered Tickseed is a easy-care plant. Recovery from Southern Blight takes approximately 21 days with proper treatment.

Unlike bacterial infections, Southern Blight on Large-flowered Tickseed can be managed with organic fungicides.

🔍 What Does Southern Blight Look Like on Large-flowered Tickseed?

• Brown to black lesions on stem near soil line
• Water-soaked appearance on lower leaves
• Sudden and permanent wilting of entire plant within days
• White mycelium radiating from plant base onto soil surface
• Spherical tan to reddish-brown sclerotia (1-2mm)
• Yellowing and necrosis of foliage
• Crown and root rot
• On fruits: sunken yellow lesions turning water-soaked

❓ What Causes Southern Blight on Large-flowered Tickseed?

→ Soilborne fungus Athelia rolfsii surviving through sclerotia
→ High temperatures (25-30°C / 77-95°F)
→ High soil moisture and relative humidity above 90%
→ Acidic soil (pH below 7, especially pH 2-5)
→ Spread through infested soil and plant debris
→ Contaminated tools, irrigation water, and transplants
→ Contaminated mulch or compost
→ Plant stress and stem injuries

💊 How to Treat Southern Blight on Large-flowered Tickseed?

TLDR: Treat Southern Blight on Large-flowered Tickseed with quick treatment (~11 days) or organic (~21 days). Large-flowered Tickseed has moderate susceptibility to this disease.

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Quick Fixes

Step 1

Remove infected plants IMMEDIATELY with roots and soil

Step 2

Apply azoxystrobin drench to adjacent plants

Step 3

Spray mancozeb on base of all plants in area

Step 4

Drastically reduce irrigation

Step 5

Reapply fungicides every 7-10 days for 3 weeks

🌿

Organic Treatment

Step 1

Remove diseased plants and 3 inches of contaminated soil

Step 2

Solarize area with clear plastic for 6 weeks

Step 3

Incorporate compost rich in Trichoderma

Step 4

Adjust soil pH with lime

Step 5

Improve drainage and plant spacing

Step 6

Apply preventive bicarbonate spray biweekly

🛡️ How to Prevent Southern Blight on Large-flowered Tickseed?

TLDR: Prevent Southern Blight on Large-flowered Tickseed with 10 essential preventive care practices.

✓ Carefully inspect transplants for sclerotia before planting
✓ Avoid planting in fields with history of infestation
✓ Maintain soil pH above 7 (lime reduces sclerotial germination)
✓ Improve plant spacing to increase airflow
✓ Use high-quality mulches from reputable suppliers
✓ Rotate with non-host crops (corn, wheat, barley) for 2-3 years
✓ Avoid overwatering and excessive soil moisture
✓ Disinfect tools between plants
✓ Deep plow (8-12 inches) to bury sclerotia
✓ Remove symptomatic plants and weeds immediately

🌱 How to Care for Large-flowered Tickseed to Prevent Southern Blight?

💧 How to Water

Water deeply every 7 days during dry spells. Avoid waterlogged soil, which is the primary cause of problems for Coreopsis. Once established, it tolerates long periods without rain.

☀️ Lighting

Requires full sun (at least 6 hours of direct sunlight per day). In lower light conditions, the plant tends to become leggy and produce fewer blooms. Avoid shaded environments.

🪴 Ideal Soil

Prefers well-drained, sandy, or rocky soils. Does not tolerate heavy clay or waterlogged soils. The ideal pH is between 6.0 and 8.0. It does not require fertile soil—excessive nutrients promote foliage growth at the expense of flowers.

Frequently asked questions

Can Southern Blight kill my Large-flowered Tickseed?

Yes, without treatment, Southern Blight can be fatal to Large-flowered Tickseed. Early detection and treatment are key.

How long does Large-flowered Tickseed take to recover from Southern Blight?

With proper treatment, recovery takes approximately 21 days. Without treatment, it can take significantly longer.

Is Southern Blight contagious to other plants near Large-flowered Tickseed?

Yes, Southern Blight can spread to nearby plants. Isolate the affected Large-flowered Tickseed immediately.

See more: Large-flowered Tickseed → See more: Southern Blight →