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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Carrot > Yellow, purple or red leaves

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Carrot > Leaves > Yellow, purple or red leaves

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  • Image: Aster Yellows 1
  • Image: Aster Yellows 2
  • Image: Aster Yellows 3

Aster yellows
Aster Yellows Phytoplasma

  • Older leaves first yellow, then turn a reddish-purple
  • Leaves may become twisted
  • New leaves are small, weak, pale and clustered in a short bunchy top
  • Numerous hairy secondary roots develop in lines along the root
  • Carrot has a bitter taste and may be off color
  • Infected plants are scattered randomly through the field, and may flower in year one
  • More information on Aster Yellows...
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  • Image: Cercospora Leaf Blight 1
  • Image: Cercospora Leaf Blight 2
  • Image: Cercospora Leaf Blight 3

Cercospora leaf blight
Cercospora carotae

  • Leaves develop roughly circular purplish brown spots with a gray center
  • Leaf tissue around spots turns yellow, leaf margins may darken and curl upward
  • Many leaf spots can grow together resulting in leaf wilt and death
  • Lesions apparent throughout old and new leaves
  • Roots are not directly infected, but may be small due to severe leaf damage
  • More information on Cercospora Leaf Blight...
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  • Image: Northern Root Knot Nematode 1

Northern root knot nematode
Meloidogyne hapla

  • In severely infected plants, carrot tops may be stunted, yellow, and wilt during the day
  • Tap root is stunted, deformed, or forked
  • Many fibrous roots may be present
  • Many small round to irregular lumps and swellings can be found on both the tap root and fibrous roots
  • More information on Northern Root Knot Nematode...
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  • Image: Bacterial Leaf Bight 1

Bacterial leaf blight
Xanthomonas campestris pv. Carotae

  • Leaf spots start small, circular, light brown to tan
  • Eventually spots become elongate; dark brown with yellow edges
  • Infection progresses down the leaf
  • Severely infected leaves, yellow, wilt and die
  • Lower leaf surface is very shiny, and may be sticky in wet weather
  • Young leaves can become distorted
  • Roots are not directly infected, but may be small due to severe leaf damage
  • More information on Bacterial Leaf Bight...
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  • Image: Pythium Root Dieback 1

Pythium root dieback
Pythium spp.

  • Carrot root is short stunted and may be forked or misshapen
  • Carrot top may yellow and wilt if root damage is severe
  • Horizontal lesions (1/10 cm to 1 cm) may appear on the surface of the root
  • Common in heavy wet soils and organic soils
  • More information on Pythium root dieback...
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  • Image: Bacterial Soft Rot 1
  • Image: Bacterial Soft Rot 2

Bacterial soft rot
Erwinia carotovora subsp. Carotovora

  • Rotted sections of the root may dissolve into liquid when carrots are pulled
  • Dark sunken, soft mushy cavities may form in the root
  • Eventually part or all of the root becomes soft, watery, and slimy
  • When root damage is severe, leaves turn yellow and wilt
  • A foul odor may be present with the rot
  • Common in very wet heavy soils
  • More information on Bacterial soft rot...

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