Karnal bunt

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​​​​​​​​​​​ Infected pieces of grain with karnal bunt that have black masses of spores on sections of the grain. Each piece of grain varies in the severity of infection.


Karnal bunt

Exotic to Australia

Features: A fungal disease that causes broken hollow (bunted)
grain, powdery masses of dark spores, and a strong fishy odour
Where it's from: India originally, but now also Afghanistan,
Brazil, India, Iran, Iraq, Mexico, Nepal, Pakistan, South Africa
and United States
How it spreads: ASpores spread easily on infected wheat seeds,
soil, agricultural products, clothing, machinery and on the wind
At risk: Wheat, durum wheat, triticale

Grains of wheat infected with Karnal bunt
L.A. Castlebury USDA-ARS SBML, PaDIL

Report it


Keep it out

Karnal bunt (also called partial bunt) is caused by the fungus Tilletia indica which infects grains at flowering. It reduces grain quality through the production of masses of powdery spores that discolour the grain and grain products. It is recognised by a fishy smell which taints the grain.

The name comes from the city in India, Karnal, where the disease was first identified. Unlike other bunt diseases, only some grains are affected on each wheat ear.

If Karnal bunt made it to Australia, it would have a major economic impact—over 45 international markets would reject our grains and grain prices would plummet.

The fungus would be almost impossible to eradicate once here since its spores can persist in soil for up to four years and they can be carried over long distances by wind.

Importing goods

To keep Karnal bunt out of Australia, never ignore Australia’s strict biosecurity rules.

Import shipments may need to be treated and certified, so before you import, check our Biosecurity Import Conditions system (BICON).

What to look for

Grain that:

  • has a blackened and sooty appearance
  • gives off a fishy smell
  • crushes in hand producing a greasy black powder.
An ear of wheat with some of the grains infected with Karnal bunt. Ruben Duran, Washington State University, Bugwood.org
Bunted wheat grains. Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org


Where to look

Crops that can be affected:

  • wheat
  • durum wheat
  • triticale.


Infested grain or imported agricultural equipment that is contaminated with infested grain pose the greatest risk of Karnal bunt making it to Australia.

Growers and grain handlers

  • Since only a few grains in each wheat head are infected, it is easiest to detect symptoms after the grain has been harvested.
  • Check harvested grain regularly.
  • Note any unpleasant or fishy smell.
  • Look for discoloured grey or black seeds.

What to do

If you think you’ve found Karnal bunt in grain:

  • do not disturb the infested produce (this may be as simple as closing the doors on a shipping container or sealing a silo)
  • take a photo.
  • collect a sample, if possible to do so without disturbing the infested produce.

Read the detail


Last reviewed: 28 August 2020
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