Fusarium stalks and ear rot of maize

C/O: Fusarium verticillioides

          Telomorph: Gibberella moniliformis = G. fujikuroi

Symptoms:

• The plants have a stalk rot and/or ear and kernel rot.
• With Fusarium, diseased kernels are isolated or in patches on the ear, especially on kernels damaged by insects such as European corn borer and earworms.
• Fusarium-affected kernels can appear tan or brown (Figure 1).
• In cases where fungal growth is visible on the ear, infected kernels will appear white to pink or salmon-colored (Figure 2).
• In some cases, the kernels will have white streaks .This is called the “star burst” symptom and is caused by the pathogen growing under the kernel pericarp (seed coat) (Figure 3).

• 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.

• In all three species, the disease symptoms are similar, but only F. verticillioides and F. proliferatum produce fumonisins.

  • Fumonisins can cause equine leukoencephalo-malacia (ELEM, also called blind staggers) and porcine pulmonary edema. In humans, several studies have associated fumonisins with cancer and birth defects.

Favorable condition:

• Warm temperatures (80-100°F).
• Wet midseason follows early season dry weather.

Survive and spread:

• Soil, seed and air borne disease
• Survive: overwinter as mycelium, macro and micro conidia in corn residue, other dead plant residue, and in corn seed.
• Spread: Spores are spread by wind and splashing water

Management:

• 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 pre harvest to determine stalk condition. Schedule harvest based on stalk quality as well as grain moisture