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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Vegetable > Cauliflower > Yellowing leaves

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Cauliflower > Leaves > Yellowing leaves

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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
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Bottom Rot/Head Rot
Rhizoctonia solani

  • Leaves turn yellow/brown and wilt
  • 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
  • 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: Club Root 1
  • Image: Club Root 2
  • Image: Club Root 3

Club Root
Plasmodiophora brassicae

  • Leaves turn pale yellow, wilt during hot, sunny days, and recover at night
  • Young plants may die
  • Older plants fail to develop a head (blindness)
  • Roots are swollen in to large spindle shaped tumor like galls
  • Common in wet soils with a low pH (acidic)
  • More information on Club Root
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  • Image: Aphid 1
  • Image: Aphid 2
  • Image: Aphid 3

Cabbage/Green Peach/Turnip Aphid
Brevicoryne brassicae, Myzus persicae, Lipaphis erysimi

  • Leaves become yellow and curled
  • Plants are stunted and head may be deformed
  • 1/16 to 1/8 inch long, soft-bodied and pear-shaped
  • Aphids are present throughout the growing season
  • More information on Aphids
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  • Image: Cabbage Maggot 1
  • Image: Cabbage Maggot 2

Cabbage Maggot
Delia radicum

  • Leaves turn yellow and may wilt
  • Maggot feeds on roots
  • Plants may be stunted
  • Maggot is legless and yellow-white in color
  • Present in early May and mid-June
  • More information on Cabbage Maggot
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  • Image: Nitrogen Deficiency 1
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Nitrogen Deficiency

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