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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Cabbage > Discolored head

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Cabbage > Head > Discolored head

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  • Image: Downy Mildew 1
  • Image: Downy Mildew 2
  • Image: Downy Mildew 3

Downy Mildew
Peronospora parasitica

  • Numerous black sunken spots can form on infected heads
  • Gray-white sunken leaf spots which are often angular and restricted by the leaf veins
  • Leaf tissue around the spots turns yellow
  • Fuzzy gray growth can be seen on the underside of the leaves
  • Disease is common in cool wet weather
  • More information on Downy Mildew
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  • Image: Black Rot 1
  • Image: Black Rot 2

Black Rot
Xanthomonas campestris

  • Yellow V-shaped lesions develop on margin of leaves, the point of the v follows a vein towards the base of the leaf
  • As infection continues, leaves wilt, turn yellow and eventually turn brown and die
  • Black veins can be seen in infected leaves, petioles and stems
  • Sticky yellowish liquid bacterial ooze may be seen if infected veins are cut
  • Disease favored by hot, humid conditions
  • More information on Black rot
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  • Image: Fusarium Wilt 1
  • Image: Fusarium Wilt 2

Fusarium Wilt (Yellows)
Fusarium oxysporum f.sp. conglutinans

  • Plant has a yellowish-green overall color that often occurs only on one side of the plant
  • Lower leaves yellow first, yellowing progresses up the plant
  • Affected leaves wilt, eventually turn brown, become dry and brittle, and may fall off
  • Stem and midrib of the leaf curve to one side
  • Veins in affected leaves are yellowish brown
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  • Image: Head Rot 1

Bottom Rot/Head Rot
Rhizoctonia solani

  • Bottom of lower leaf develops sunken, black, and elliptical lesions parallel to the midrib of the leaf
  • Dark cobweb-like or cotton-like fungal growth develops between diseased leaves
  • Leaves turn yellow/brown and wilt
  • Disease may be limited to the lowest leaves or may start at the bottom of the plant and move up through wrapper leaves into the cabbage head
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  • Image: Calcium Deficiency 1
  • Image: Calcium Deficiency 2

Calcium Deficiency

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