Blunk/Stinking Smut (Tilletia tritici)
A disease specific to wheat, bunt is well-known for smelling of rotting fish. The disease replaces the grain in infected ears with balls of spores. When these balls are ruptured by the combine, the spores are released as a sooty cloud, contaminating not just the seed in the combine but also the soil, nearby crops and the grain store.
To spot bunt, you need to look for yellow streaks on flag leaves, and stunted plants with dark grey-green ears and slightly open glumes. Cases of bunt are rare, but usually occur when farm saved seed has been repeatedly sown without a single purpose dressing. The disease spreads very quickly as each bunt ball contains millions of spores. As well as contaminating grain, bunt can also contaminate any machinery or equipment it comes into contact with.