Stalks feel spongy when squeezed and may be easily crushed or crimped at lower internodes
Plants may lodge when pushed sideways or impacted by wind
Fusarium vs. Gibberella
Fusarium may look similar to Gibberella stalk rot
Closely related fungi cause these diseases
Distinguish by inner stalk color
Fusarium - white/pink/salmon
Gibberella - red/pink
Facts on Fusarium Stalk Rot
Caused by Fusarium verticilioides fungus (formerly called Fusarium moniliforme), found everywhere corn is grown
Also infects sorghum, sugarcane, wheat, cotton, banana, pineapple and tomato
Overwinters as mycelia in infected crop debris, spread by wind and rain splash
Can infect the plant directly through the roots, causing root and lower stalk rot
Can also infect at the nodes when dispersed to leaves and washed down into the sheath
Favored by warm, relatively dry weather; plant stress following pollination; and other diseases
Disease generally progresses during reproductive stages of corn development
Typically occurs in a complex with other root/stalk rots including Gibberella, Diplodia and anthracnose
European corn borer adults have been shown to vector the disease from plant to plant. Corn borer larvae create wounds that allow the fungus to enter the plant.
Disease Cycle
Impact on Crop
Interference with translocation of water and nutrients during grain fill
Affected plants have poorly filled kernels (low test weight), resulting in yield reduction
May lead to premature death in some cases, magnifying test weight and yield reductions
Broken and lodged stalks
Slows harvest
May result in ears not harvested
May reduce grain quality if ears contact ground
Fungus may also infect corn ears
Management of Fusarium Stalk Rot
Select hybrids with good stalk strength and resistance to leaf diseases
Rotate crops
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 to 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. Schedule harvest based on stalk quality as well as grain moisture