Yours, Etc.: Origins and Uses of 8 Sign-Offs
disease of wheat, rye, and other grasses caused by the fungus Tilletia. Normal kernels are replaced by smut "balls" containing powdery masses of brownish-black spores having a dead-fish odour. Two forms of bunt infect wheat: dwarf bunt, caused by Tilletia caries, results in plants a fourth or half normal size; common bunt (T. foetida) normally stunts wheat only a few inches. Smut balls break open and contaminate healthy kernels during harvest. Bunt spores may remain alive in dry soil for several years. Seedling infection occurs shortly after kernels germinate in cool, fairly dry soil. At maturity, a mass of smut spores (teliospores) replaces the entire kernel. Bunt is controlled by using smut-free, fungicide-treated seed of resistant varieties. Carboxin (Vitavax) seed treatment is effective against both soil- and seed-borne bunt spores.