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Black Spots in Dahlia

verifiedReviewed by the GreenScout Team

Dahlias produce some of the most spectacular flowers in the garden from mid-summer until first frost

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Dahlia care requirements

These care conditions are most relevant to black spots in Dahlia. Check each one as a potential cause.

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Humidity
Moderate.
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Water
Regularly and deeply — keep evenly moist.
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Temperature
Not frost hardy. Plant tubers after last frost.
symptoms

Symptoms to look for in Dahlia

  • fiber_manual_recordBlack or dark brown spots
  • fiber_manual_recordSpots with yellow halos
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Common causes in Dahlia

  • fiber_manual_recordFungal disease (black spot)
  • fiber_manual_recordBacterial infection
  • fiber_manual_recordSunburn
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How to diagnose black spots in Dahlia

Fungal spots: often circular with yellow margins. Sunburn: irregular bleached patches turning black.

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How to treat black spots in Dahlia

Remove affected leaves. Apply fungicide. Adjust sun exposure.

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Preventing black spots in Dahlia

Avoid wetting foliage. Provide adequate spacing. Remove debris.

Other Dahlia problems