Bunt of Wheat

Tilletia laevis, Tilletia tritici, Tilletia foetida, Tilletia caries

Ustilago tritici - imperfect stage.

Other Names:

Also referred to as Covered Smut of wheat.

Description:

Dark brown masses or balls of powdery spores replace the Wheat grains. These balls may force the glumes apart making them easier to see but they are often quite difficult to see in the head. With time the spores blow away leaving the naked stalk and a few glumes.
Infected plants are often shorter and may stay green longer than healthy plants.
During the harvesting operation the spore masses are often broken releasing a mass of powdery spores and a fishy odour.

Species Affected:

Wheat.

Biology:

Requires cool (5-150C) and moist conditions for infection.
Early sown crops often escape infection.
The fungus have adapted so that many varieties that were previously infected are now susceptible especially where the disease challenge is high.

Life Cycle:

Spores released from ruptured Bunt balls contaminate grain and soil. Under cool (5-150C) moist condition at planting the first leaf of the crop seedling is infected. The fungus develops and grows through the plant to the head where new Bunt balls are produced as the crop matures.

Origin and History:

Distribution:

Significance:

Bunted grain will not be accepted for export sale and contamination will damage our export markets. Zero tolerance level of affected grain and grain will not be accepted by CBH.

Management and Control:

Sow crops early when temperatures are greater than 150C.
Use seed from uninfected areas.
Treat seed with a fungicide.

Thresholds:

Very difficult to detect in the field. Zero tolerance levels for export grain.

Related and Similar Species:

References:

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.HerbiGuide.com.au for more information.