Gibberella Stalk Rot

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Symptoms of Gibberella Stalk Rot

Gibberella stalk rot
Corn stalks infected with gibberella stalk rot have pink to reddish coloration of pith and vascular strands.

Gibberella stalk rot

  • Rotting at roots, crown and lower internodes are symptoms of Gibberella stalk rot
  • Perithecia (small black fungal fruiting structures), may develop on the stalk surface near the node (can be scraped off with fingernail)
  • Pink to reddish coloration of pith and vascular strands (bundles)
  • Pith of the inner stalk may deteriorate leaving only the vascular bundles intact
  • Destruction of the nodal plate
  • Later stages - plant turns gray-green, internodes turn straw colored or dark brown and are easily pinched between fingers
  • Late-season snapping of stalks at the node

Gibberella vs. Fusarium

Gibberella stalk rot
Fusarium stalk rot
Fusarium stalk rot
  • Gibberella may look similar to Fusarium stalk rot
  • Closely related fungi cause these diseases
  • Distinguish by inner stalk color
    • Gibberella - red/pink
    • Fusarium - white/pink/salmon

Facts

  • Caused by the fungus Gibberella zeae
  • Occurs wherever corn is grown throughout the world
  • Infects other cereals like wheat, barley, oats and rye
  • Overwinters in infected crop residue of corn or other cereals
  • Ascospores produced in perithecia are disseminated to corn plants by wind and rain splash
  • Insect injury often allows pathogen to enter the plant
  • Can infect corn at the leaf sheaths, brace roots or roots. Infection continues from roots into lower stem
  • Secondary cycles of disease are by conidia produced within disease lesions
  • Infection often occurs after pollination. Disease can progress rapidly with warm, wet weather during corn reproductive stages
  • Environmental and physiological stresses may weaken the plant and allow disease development

Disease Cycle

Gibberella stalk rot disease cycle

Impact on Crop

  • Greatest damage to corn crop is usually caused by stalk breakage or lodging
    • Lodging slows harvest and usually results in some ears left in field
    • If ears contact ground, grain quality may be reduced
  • Stalk deterioration disrupts water and nutrient flow, and plants may die prematurely
    • Affected plants have lightweight ears and poorly filled kernels (low test weight)
  • Gibberella zeae may also infect ears

Management of Gibberella Stalk Rot

  • Select hybrids with good stalk strength and resistance to leaf diseases
  • Rotate crops. Corn following soybeans often has less stalk rot and higher yield than continuous corn
  • Use a tillage system that chops and incorporates residue to break it down
  • Do not use plant populations higher than recommended for the hybrid
  • Soil test and follow fertilizer recommendations; maintain proper nitrogen:potassium balance
  • Reduce stresses when possible - stalk rots are favored by plant stress following pollination
  • Control leaf diseases with fungicides if necessary
  • Control corn rootworm and corn borer.
  • Scout preharvest to determine stalk condition and schedule harvest based on stalk quality as well as grain moisture