Diseases and Insect Pests
Serious diseases of wheat caused by fungi include stem and leaf rust, smut, scab, seedling blight; and root rot. Less widespread damage is caused by bacteria and viruses. Wheat diseases may be controlled to some extent with fungicides and germicides. The best method of control is the use of disease-resistant hybrids. Developing such hybrids is a never-ending task, however, because many disease-producing organisms are able to mutate into forms that can feed on the new strains of wheat.
The Hessian fly is wheat's worst insect enemy. It usually attacks winter wheat, which may be protected by planting after the fly's hatching time is past. Other pests are chinch bugs, aphids, cutworms, mites, and grasshoppers. These pests may be controlled by crop rotation, sprays, and proper soil preparation. Stored grain may be attacked by meal worms.