Sorghum Ergot – Frequently Asked Questions

Post on October 8, 2025

Brent Bean, Sorghum Checkoff Director of Agronomy

What is sorghum ergot?
Ergot is a fungal disease that under the right climatic conditions, can infect sorghum heads, producing large amounts of honeydew and primarily impacts male-sterile forage sorghum. Significant infection in commercial grain sorghum fields is rare.

When did sorghum ergot appear in the US?
Sorghum ergot has been present in other parts of the world since the early 1900s and can be found in most sorghum growing countries. It appeared in Brazil in 1995 and was first detected in the United States in 1997, spreading quickly from South Texas to Nebraska.

Is ergot in sorghum toxic to cattle and other livestock?
We are not aware of any issues with toxicity in the past or present in the US caused by the ergot fungus Claviceps africana that infects sorghum. This includes forage fed as silage or hay. It is very important to note that this is not the same ergot fungus that infects wheat, rye, triticale and fescue. The honeydew itself contains very little toxin (alkaloids). In the sorghum head, instead of grain being produced, a compact, hard fungal mass called sclerotia may develop in the later stages of infection. It has a tough outer rind and a compact inner core that may be reddish brown in color and replaces kernels. Do not confuse this with dried honeydew or secondary infections. These sclerotium fall to the ground or are generally separated from the grain during processing. These sclerotia would be expected to have a higher level of alkaloids. However, it is important to note that in the High Plains, there is some question about whether sclerotia is even produced.

Is this the same ergot that infects other grasses and crops?
No. The ergot affecting sorghum in the US is Claviceps africana, a different species from those that infect wheat, rye, triticale and fescue. C. africana does not produce the same alkaloids as other ergots.

How can I identify ergot?
Ergot infection is easy to identify because of the abundance of honeydew that the fungus produces. Thick, sticky, ambered colored, syrup-like honeydew drips from the sorghum head to the leaves and to the ground, where it often dries in a white powdery like substance. The honeydew also sometimes appears as a dried brown to black colored mass in place of kernels in the sorghum head.

How does ergot spread?
The honeydew contains spores that germinate to produce secondary spores on the surface of the honeydew. These spores are then capable of being spread by the wind over long distances. Honeydew on the seed is also a source of spores.

When does ergot infection occur?
Ergot can infect sorghum during flowering when conditions are cool with relatively wet or high humidity conditions just prior to or at flowering.

How does ergot infect sorghum?
The sorghum head (panicle) contains hundreds and even thousands of small flowers (florets). Only non-pollinated florets are susceptible to ergot infection. The sorghum plant 'flowers' over a 3 to 7 day period after heading. This is when the pistil (female portion of the floret that contains ovaries) becomes viable and is receptive to pollen for fertilization. Anything that interferes with timely pollination increases the potential for ergot infection. Any unfertilized florets remain susceptible to infection.

Are there differences in sorghum varieties in ergot susceptibility?
Yes, mostly because of differences in pollen production. Commercial grain sorghum hybrids are typically very resistant to ergot infection because of the abundance of pollen that they produce. When found in sorghum, it is often in late planted sorghum, or in late emerging tillers.

Which are the most susceptible varieties or lines of sorghum to ergot?
Male sterile forage sorghum and sorghum grown for seed production are very susceptible to ergo because of the lack of pollen being produced. Once the florets are pollinated they are resistant to infection.

What is the actual toxin that is a potential issue?
Dihydroergosine is the predominant alkaloid produced by the sorghum ergot C. africana. It's very important to understand that the ergot in fescue/wheat/rye is not the same fungus that infects sorghum. These fungi produce different alkaloids than what is produced by C. africana in sorghum.

Will ergot cause harvesting issues?
Yes, if honeydew is present in high quantities harvest equipment can become gummed up, requiring frequent cleaning.

Will the honeydew go away?
The honeydew is water soluble and will wash off the sorghum plants in a good rain or sprinkler irrigation. A hard freeze will kill the plant eliminating the food source used by the fungus to produce honeydew.

Can the sorghum crop be managed to minimize ergot infection?
Yes, to some extent by avoiding planting times that may lead to poor pollination. Avoid planting sorghum at a time when cool wet conditions are present at flowering. Avoid late planting that places flowering at a time when night temperatures or early morning temperatures are cool. Avoid using male-sterile forage sorghum. These are very susceptible to ergot infection.

Will fungicide application control ergot?
Standard fungicide seed treatments should control any fungus that is on the seed surface. During the season, there are a few fungicides that are effective in preventing ergot infection. However, these must be applied just prior to flowering to be effective. Complete coverage of the sorghum head with fungicide is critical.

Will ergot survive through the winter and infect next year's crop?
Sorghum ergot cannot survive the freezing temperatures experienced in the winter months of the High Plains. However, in southern areas with mild winters, some ergot inoculant may survive and potentially infect new crops under favorable conditions.

Sources:
Sorghum Ergot - New disease threat to the sorghum industry. Joseph Krausz and Thomas Isakeit. 1998. Texas A&M AgriLife Extension. E-461.

Ergot: A new disease threat to sorghum in the Americas and Australia. R. Bandyopadhyay, Debra E. Frederickson, Neal W. McLaren, Gary N. Odvody, Malcolm J. Ryley.1998. Plant Disease: Vol.82. No.4.

Newly discovered ergot alkaloids in Sorghum ergot Claviceps africana occurring for the first time in Israel. J.A. Shimshoni, O. Cuneah, M. Sulyok, R. Krska, E. Sionov, S. Barrel, Y. Meller Harel. 2017. Food Chemistry 219:459-467,