Mycotoxins: Should you be concerned?

By Madalyn Shires and Connie Stunk et.al

Molds produce mycotoxins and these toxins can pose a hazard to animals and to people. Environmental stress caused by the weather (drought, hail, etc) or damaged crops increases the potential for mold and mycotoxin development. This article focuses on mycotoxins and how to manage them.

Molds (which are fungal plant pathogens) produce mycotoxins, but molds by themselves do not cause problems for animals, though they can be problematic in grain storage as they continue growing and reproducing thus producing more mycotoxins. The mycotoxins produced by these molds can cause significant problems for livestock and significant reduction of prices at grain elevators. 

Fungal pathogens which produce mycotoxins in corn are Fusarium graminearum (also known as Gibberella zeae) which causes stalk and ear rots and Aspergillus species which leads to ear rots. A common ear rot that does not produce mycotoxins is Stenocarpella maydis which causes Diplodia ear rot. Ergot, which is rare in corn but common in grasses, is caused by Claviceps species.

Mycotoxins with higher prevalence in corn are Aflatoxin (reduced performance/death more prevalent in drought), Zearalenone (ZEN/ZON) (reproductive problems), and DON / Vomitoxin (feed refusal). Fumonisins and T-2 toxins may occur in South Dakota, but far less frequently. We often see DON and ergot issues in wheat, other small grains, and grasses.