Bunt or stinking smut

Causal organism - Tilletia tritici

---

Control

As bunt spores lie on the surface of contaminated grain, disinfection is relatively easy using surface-acting fungicides - hence the success of copper compounds (in use from the 19th century until the 1940s) and the even greater efficacy of organomercury which began to be widely used in the UK during the 1930s and continued to be used extensively until 1992/3. It should be noted, however, that even the best fungicides may not afford a complete control of the disease. If inoculum levels are high and conditions are very favourable for infection the disease control is often reduced.
Surface acting fungicides traditionally did not control infection caused by spores in the soil. A systemic material such as Baytan is required to protect against this infection source. However, some of the newer materials such as Sibutol and Beret Gold, although not systemic, do give control of soil-borne infections. See HGCA Wheat seed health and seed-borne diseases - a guide, for more information

Note that early sowing (before spores have germinated as a result of autumn rains) favours infection from soil-borne inoculum . Late sown crops, on the other hand, are likely to suffer more severely from seed-borne infection as at lower temperatures they grow less rapidly through the susceptible seedling stage and are less able to grow away from the fungus as it grows into the plant.