Hard to believe, but fall and cooler temperatures will be here in less than a month. Soon after that, a frost will occur. Members of the sorghum family have a compound called dhurrin that will release hydrogen cyanide, commonly known as prussic acid, when plants are stressed by drought or frost. While traveling to Spencer County for a field day this week, it was noted that Johnsongrass was commonly seen in pastures. Johnsongrass, a perennial sorghum, has the potential to produce hydrogen cyanide and cause livestock death when plants are stressed. Other planted sorghums when stressed will produce hydrogen cyanide, too.
![Johnsongrass was evident in pastures while traveling to southern Indiana this week. It has the potential to produce prussic acid (hydrogen cyanide) when frosted.](https://extension.entm.purdue.edu/newsletters/pestandcrop/wp-content/uploads/sites/2/2022/08/johnsongrass.png)
Johnsongrass was evident in pastures while traveling to southern Indiana this week. It has the potential to produce prussic acid (hydrogen cyanide) when frosted. (Photo Credit: Keith Johnson)
Producers are encouraged to utilize sorghums before a frost occurs to reduce the possibility of prussic acid poisoning. Links below to a publication and video will discuss ways to reduce the fear of prussic acid poisoning.
In the near future, dhurrin-free sorghums will be available for seeding as a result of Purdue University work conducted by Dr. Mitch Tuinstra’s research group, most notably Dr. Shelby Gruss. Unfortunately, Johnsongrass will remain to be concern even when dhurrin-free sorghums are available.