Enemies of Wheat
Wherever wheat grows there are many enemies that attack it, reducing yields or even destroying the crop. The worst enemies are diseases—caused by fungi, bacteria, or viruses—insects, and weeds. In most regions fungal diseases are the greatest threat to wheat crops. Many problems are controlled by using resistant varieties or by using herbicides and pesticides to destroy or deter the invading enemy.
Fungi
Leaf rust, stem rust, and stripe rust are fungal diseases that infect leaves and stems. They are known as rusts because the red spores they produce often make the plant look rusty. These diseases spread when spores are released and are carried on the wind to other wheat plants. There they germinate and use the nutrients in the wheat plant to grow and develop many more spores. Rusts spread quickly during moderate temperatures and high humidity when plants are wet from dew or rain. Severe rust damage can reduce wheat yields by 25 percent or more. Many wheat varieties have at least some resistance to rusts.
The spores of smuts land on the wheat just at flowering time and infect the developing kernels. The next year, the fungus grows inside the plant and usually replaces the kernels with a mass of fungal tissue and spores, which can be released to infect other wheat plants.
S 34° 14.362′ E 139° 05.504′