Fusarium ear rot (Fusarium verticillioides)

Single kernels with white or grayish mould

Fusarium ear rot: biology

Fusarium ear rot is a common corn ear disease caused by Fusarium verticillioides. The Fusarium fungi overwinter in the soil and on crop residue. Soil-borne hypha or air-borne spores survive in a variety of conditions; warm and wet weather two to three weeks after silking provides favourable environmental conditions for the disease to progress and thrive. Sites of previous kernel damage due to insects, animals or mechanical means are more prone to infection.

Fusarium ear rot: damage description

Fusarium infection is characterized by white, grayish or pinkish mould on single kernels scattered around the cob. White streaks, referred to as “star-bursting”, can be seen on kernel surfaces. Multiple infected kernels can be scattered around the cob, differentiating Fusarium ear rot from Gibberella, which typically appears as clumps of infected kernels.

Fusarium ear rot reduces yield and grain quality. Fusarium verticillioides produces the mycotoxin fumonisin, which can be fatal to pigs and horses, and is a human carcinogen.

Fusarium ear rot: management

Scout for ear rot from the R5-R6 growth stages (dent to black layer/maturity). Harvest early if more than 10% of plants display ear rot. Dry and cool harvested corn quickly and test grain for mycotoxins before feeding it to livestock.

Plant seed with insect resistance traits, since corn damaged by insect feeding is more susceptible to infection.

The best timing for Fusarium management with fungicides is at the R1 stage (silk emergence):

  • R1 is the first stage of the reproductive phase
  • Silks remain receptive to pollen for up to 10 days after silk emergence
  • The window of application to optimize fungicide performance is about 7 days staring at R1
Once the crop reaches R2, the optimal application window has closed.

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