Ergot Comments for Silage Sorghum

Post on October 1, 2025

Ergot Comments for Silage Sorghum

Brent Bean, Sorghum Checkoff Director of Agronomy

• Caused by the fungus Claviceps africana, and produces an alkaloid mycotoxin.
• Survives on crop residue on the soil surface. Also can survive on the seed coat. Seed treatments should be effective on seed-born ergot. A hard freeze should kill it on the surface.
• Only infects sorghum during flowering.
• Cool temperatures and high humidities are especially conducive for ergot infection.
• Insecticide preventative can be effective, but must be applied prior to infection, i.e. early flowering.
• Fungicides:
  • Propiconazole (Tilt, many generics) - there is a 30 day pre-harvest interval for forage
  • Several two way mixes of propiconazole and azoxystrobin
  • Flutriafol (Topguard) - labeled for grain sorghum only.
  • Adastrio, a relatively new fungicide from FMC is labeled (3 way mix) containing flutriafol. Labeled for grain sorghum only.
• Honey dew and fungus growth will start occurring with cool, damp weather
• For seed export, a company may need to get TDA to certify that no ergot is present. Or seed can be sent to a lab for testing.
• From Dr. Ted McCollum, former TAMU Beef Cattle Specialist at Amarillo
  • The alkaloids produced by the ergot are the concern. Unlike nitrates, the ensiling process will not reduce the alkaloids present in the ensiled product. Depending on the concentration of alkaloids, the silage will have to be fed on a mixed ration to dilute the concentration in the total diet.
  • The alkaloids have less impact on performance in cool/cold months, so winter feeding focus might aid in using the silage.
  • Based on some Australian work, greater than 1.0 ppm (dry matter basis) ergot alkaloid will depress performance. This was based on work with fescue.
• Keep in mind these comments are based on fescue silage, so we cannot be sure they will translate to sorghum silage. Also, the concentration level should be based on the TOTAL DIET RATION.

Resources:
Scientists and specialists at Texas A&M Research and Extension Amarillo have been involved in discussions on ergot and are currently conducting and planning research studies to address ergot infected sorghum.

• Contacts
  • Jourdan Bell, Extension Agronomist
  • Juan Piniero, Extension Dairy Specialist
  • Jason Smith, Extension Beef Cattle Specialist
  • Nolan Anderson, Research Plant Pathologist