Grain bane is a term used to describe two different types of fungi that can cause serious damage to crops. The first is SMUT, a type of fungus that causes black spots on grains such as wheat, barley, and oats. The second is ERGOT, a fungus that can cause hallucinations and other neurological symptoms in humans if ingested. Both of these fungi can cause significant losses in crop yields and can have a major impact on food security.