Fusarium Yellows and Root Rot

Fusarium oxysporum 

 

Identification

  • Fusarium yellows and root rot are caused by a fungus
  • Fusarium is a vascular wilt and root rotting disease of sugar beets
  • Found in all sugar beet production areas to some extent
  • Survives in soil for many years
  • Spreads by moving infected tare dirt
  • Infected area will grow slowly
  • Can be confused with seedling disease caused by Aphanomyces , Pythium, Phytophthora, or Rhizoctonia
  • Flooding, tillage, root aphids, and wind damage can cause similar symptoms

 

Detection 

  • Appears early to mid-summer 
  • Vascular system in the root becomes blocked and at later stages discolored
  • Wilting of leaves
  • Older leaves show yellowing between veins and “half leaf” yellowing before dying
  • Infects root tip and progresses upward
  • Vascular discoloration, usually a reddish brown
  • A crosscut of the beet will show the darkened vascular rings
  • Root tip may become completely blackened in advanced infections
  • Under high soil fungus populations, damping-off of seedlings can occur
  • Plant regains vigor overnight, but wilt rapidly during the day as temperatures rise

 

Cause of Damage

  • Plugged vascular system blocks water and nutrients from moving within the beet

 

Beet Damage

  • Wilting of beets 
  • Reduced sugar and tonnage
  • Sugarbeet may not survive, unless temperatures remain cool
  • Poor storage

 

Control

  • Lengthen sugarbeet rotation
  • Early planting will result in more growth before favorable temperatures for development occur
  • Resistant varieties