When the wheat matures, the fields wave with golden hues, and people harvest joyously, celebrating the bountiful yield. During the harvest, we often find some black wheat spikes among the golden ones, which bear no grains at all. What is this black substance? Why does this phenomenon occur in wheat? It turns out this is due to a disease known as smut. There are several types of smut diseases, including stinking smut and loose smut in wheat, covered smut and loose smut in barley, and covered smut and loose smut in oats. The common characteristic of these smut diseases is that they infect the spike, turning it black and preventing the formation of wheat kernels, resulting in a lot of black powder.
These black spikes are formed by the infection of smut fungi. The black fungi cling to the surface of wheat seeds and hide inside the wheat. Once the wheat is sown and begins to germinate and grow, the hidden fungi on the grains also sprout and start to grow, attacking the wheat germs. As the wheat continues to grow, the fungi also grow and continuously reproduce, producing many black spores that replace the normally growing wheat kernels. Therefore, the wheat spikes that emerge are black and contain many black powdery spores. We call these spores smut spores. These spores can be blown around by the wind, but some, like stinking smut and covered smut, have a hard thin membrane around them on the outside of the spike, which the wind cannot disperse. However, they may be mixed with good wheat kernels and can cause damage again the following year.
Therefore, when we see these black spikes in the wheat fields, we must pull them out and burn them.