Common and Dwarf Bunt

Common bunt (stinking smut)
Tilletia tritici (Bjerk.) G. Wint. in Rabenh
Tilletia laevis Kühn in Rabenh

Dwarf bunt
Tilletia controversa Kühn in Rabenh

  1. Symptoms: The main symptoms caused by these three species are fungal structures called "bunt balls," which resemble kernels but are completely filled with black teliospores. The bunt balls of common bunt, caused by T. tritici and T. laevis, are about the same size and shape as the kernels they replace (picture on left) those of dwarf bunt, caused by T. controversa, are more nearly spherical (picture on right). When bunt balls are crushed, they give off a fetid or fishy odor. Infected spikes tend to be bluish green in color (or darker), and the glumes tend to spread apart slightly; the bunt balls often become visible after the soft dough stage (picture below). A slight reduction in plant height is typical of common bunt, while a pronounced reduction in height is typical of dwarf bunt.
  2. Development: Spores lying dormant in the soil or on seed germinate and infect emerging seedlings. Infection is favored by cool temperatures during germination. The disease develops systemically, with visible symptoms appearing after heading.
  3. Hosts/Distribution: Wheat and (less commonly) triticale are affected by these diseases, as are several other related grasses. Common and dwarf bunts can occur worldwide. Both are limited to temperate climates; dwarf bunt occurs in areas having prolonged snow cover.
  4. Importance: Considerable yield losses can occur when susceptible cultivars are grown or chemical seed treatments are not used.

Common and Dwarf Bunt Common and Dwarf Bunt Common and Dwarf Bunt Common and Dwarf Bunt

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