Mycotoxins are natural, toxic substances produced by fungi that can grow on or within grain in the field.  Extreme weather events, increased temperatures and other factors can facilitate the growth of toxic fungi in crops, increasing the risk of mycotoxin contamination.

There are two primary kinds of mycotoxins:

  1. Aflatoxin
  2. Deoxynivalenol (DON), commonly referred to as vomitoxin.

Both aflatoxin and DON are highly associated with ear rots. Fields that have a noticeable amount of ear rot should be harvested separately if possible and dried down to 15% before storage.

Deoxynivalenol (DON), also referred to as vomitoxin, is most closely associated with gibberella (gibberella zeae) ear rot and has been most concerning to growers in 2022. Pink or whitish mold found at the tip of the ear after it has been peeled back is the characteristic sign of this disease.

DON mycotoxin has been most concerning to growers in 2022.

Some factors that can increase risk for gibberella ear rot include:

  • Corn after corn (especially if the previous crop was infected with gibberella ear rot).
  • Cool wet weather following silking.
  • Planting a full season product out of zone.
  • Planting a hybrid with a tight husk.

Fungicides can play a role in suppression of both aspergillus and gibberella, but the timing of spray applications on actively silking hybrids is critical.

Some mitigation strategies growers can use to minimize the risk of mycotoxins:

  • Plant a variety of different maturing hybrids. This will help to spread out risk around infection timing (at silking) and disease propagation later during grain-fill, depending on environmental conditions.
  • Use hybrids that are in maturity for your area and limiting the number of full season hybrids that are planted outside of maturity zone.
  • Apply fungicides to control foliar diseases and optimize kernel depth and grain-fill. Consider earlier applications of fungicides, especially those that contain triazole chemistry when the corn is actively silking to help suppress aspergillus and gibberella. Please note that additional applications may be necessary, especially if tar spot becomes an issue, later in the growing season.

If you have grain that was harvested from a field with Gibberella ear rot, it is highly likely that it contains mycotoxins. Unfortunately, there are no commercially available treatments to reduce vomitoxin levels in stored grain, but proper storage can help reduce the likelihood of levels increasing while in storage. Warm, moist pockets in the grain can promote additional mold development, which ultimately leads to higher toxin levels.

Storage Tips to Reduce Mold Development

  • Be sure to store grain below 15% moisture to minimize further mold development.
  • If mold is found, take a sample, and get it analyzed to determine the level of toxins present.
  • If you have a load that tests high for vomitoxin, contact your insurance adjuster and ask the elevator to keep a sample.
  • Check grain periodically for mold, insects and temperature.
  • Be sure to thoroughly clean grain bins between seasons to prevent cross contamination.

Have questions or want to learn how you can take advantage of further recommendations for your fields? Contact your local Mercer Landmark CPA today.