Common bunt of wheat

Symptoms

• The disease shows up only at the beginning of milk ripeness of the grain. An infected ear is somewhat flattened, intensely green with a blue tinge, and the glumes are developed.
• When wheat reaches full ripeness, the difference in colour between healthy and infected ears almost disappears.

Signs of the pathogen

In an infected ear, smut balls form instead of grains. They are black, rounded structures containing many small chlamydospores.

When to look

The assessment is made on sheaf samples during field inspection (approbation) of the crops. The sheaf is taken from the end of milk ripeness to the start of wax ripeness of the grain, separately for each variety.

How to count

• The sheaf for each variety is made up of samples of 10–15 stems taken in a row at one place, and the sampling places should be equally spaced across the field. On an area of up to 200 ha, the sheaf should contain at least 1000 stems; on up to 450 ha, at least 1500 stems.
• Infection is determined as the percentage of infected ears out of the total number of ears.

No rate and no spray timing here: both come from the label and the register.

Agronomy

• To avoid smut infection of crops, follow good agronomic practice, in particular good-quality soil tillage.
• Follow crop rotation and spatial isolation, clean seed thoroughly, disinfect containers and seed drills, and grow disease-resistant varieties.

Source of infection

The sources of infection for smut diseases of small-grain cereals are mainly in the seed.

Every fact rests on a quote from its source, and each quote was checked against the page it is printed on.

1. EPPO Global Database · European and Mediterranean Plant Protection Organization
2. Станкевич С. В., Положенець В. М., Немерицька Л. В., Журавська І. А., «Моніторинг хвороб сільськогосподарських культур», навчальний посібник, 301 с. · Інститут біоенергетичних культур і цукрових буряків НААН, Державний біотехнологічний університет; Житомир: Рута, 2022 · p. 154
3. Прогноз фітосанітарного стану агроценозів України та рекомендації щодо захисту рослин у 2025 році · Держпродспоживслужба, НААН, НАН · p. 48
4. Photos: Agronom, Wikimedia Commons, CC BY-SA 3.0 · This image was created by user mosatart at Mushroom Observer , a source for mycological images. You can contact this user here ., Wikimedia Commons, CC BY-SA 3.0