This document discusses common bunt/stinking smut/hill bunt, a fungal disease that infects wheat. It is caused by the fungi Tilletia tritici, T. laevis, and T. controversa. The disease spreads through teliospores that can survive in soil or on seed for many years. Infection results in black, smelly spore masses forming in place of wheat kernels. Integrated management includes using pathogen-free seed, resistant varieties, and fungicide seed treatments. The disease was historically devastating but losses have reduced with fungicide use.

1. COLLEGE OFAGRICULTURAL TECHNOLOGY
(Affiliated to Tamil Nadu Agricultural University, Coimbatore-3)
Kullapuram (Po), Via Vaigai Dam, Theni-625 562
COMMON BUNT/ STINKING SMUT/ HILL BUNT OF
WHEAT
Student: Course Teacher:
P. Deepa Gnana Sundari Dr. Parthasarathy .S
2015021026 Asst. Prof., Plant Pathology.

2. Common Bunt/ Stinking Bunt/ Hill Bunt
Local Names
Hill Bunt - Kotumai Malaikutti.
Stinking Bunt - Kotumai Alukippothal.
Other Names
Covered Bunt - Kotumai Mutappattiruthal

3. Pathogen
Tilletia tritici (syn. T. caries) and T. laevis (syn. T.
foetida), which are distributed throughout the world
on spring-planted and autumn-planted wheat.
T. controversa, occurs on autumn-planted wheat and
also on numerous genera of winter annual grasses.

4. Distribution in World
• Asia
• Australia
• North and South America
• Europe

5. Distribution in India
• Haryana
• Punjab
• Himachal Pradesh
• Uttar Pradesh
All the Wheat growing regions in India.

6. Historical Significance
• Stinking bunt is a disease that was recognized early in
agricultural development because of its prominent
symptoms and signs, e.g., black smelly masses of spores
in the heads of wheat.
• M. Tillet, a French biologist experimented with the black
spore masses in 1755.
• Even though this was prior to the time when the "germ
theory of disease" was accepted, he did show that the
spores were associated with the disease.

7. • However, he believed that it was a "poisonous entity"
associated with the black spore masses that actually
caused the disease, not the fungus itself. It wasn't
until nearly 100 years later that Anton de Bary, the
Father of Plant Pathology, confirmed the parasitic
nature of the smut fungus.

8. Economic Significance
• From the late 1800s until the 1930s, stinking smut
was a devastating disease of wheat, particularly in
winter wheat grown in the Pacific Northwest.
• Infection levels over 20% were common in
Washington in the early 1900s, and between 25-50%
of the Kansas wheat crop was lost to stinking smut in
1890.

9. • Because of the dusty spore masses released during
harvest, many "thresher" explosions occurred.
• Static electricity that developed around the combine
machinery ignited the teliospore dust released by the
combine.
• In 1915, 160 such explosions were reported in
Washington.

10. • One can visualize the panic that must have developed when a
"thresher-combine" pulled by a 20-40 horse team caught fire in
the middle of a wheat field from such a smut dust-induced
explosion.
• Only when the organic mercury and several seed treatments
became available after 1930 did losses from smut drop to
much lower levels.
• Today, losses from smut rarely occur unless a grower chooses
not to plant treated seed.

11. Pathogen and its characters
• Low Bunt - Tilletia caries ( (DC.) Tul. & Tul.) 1847)
(syn. Tilletia tritici (Bjerk.) )
• High Bunt - Tilletia laevis ( Kuhn.)
(syn. Tilletia foetida (Wallr.) )
• Dwarf Bunt - Tilletia contraversa (Kuhn.) 1947)
(syn. Tilletia calospora (Pass.) )

12. Tilletia laevis
T. laevis occurs in the wetter areas of the mid-west and eastern United States.
Teliospores of T. laevis have reticulate, globose and smooth walled. No
resting period. Germinate to produce primary sporidia which unite to form
‘H’ shaped structure.
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycetes/Pages/
StinkingSmut.aspx

13. Tilletia caries
Tilletia tritici is found in the drier western areas of the United States.
Teliospores of T.tritici have have reticulate, globose and rough
walled which gives them a “warty” appearance. .
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycete
s/Pages/StinkingSmut.aspx.

14. Tilletia controversa
• Teliospores of T. controversa are yellow-brown to
red-brown, globose, mostly 19-24 µm diameter,
mature spores are typically surrounded by a hyaline
gelatinous sheath 1.5-5.5 µm thick.
• In median view, the exospore is reticulate, with
relatively large, regular, polygonal areolae, 1.5-3 µm
high and 3.5 µm diameter.

15. https://www.google.co.in/search?q=dwarf+bunt+of+wheat+images&dcr=0
&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjV6pXUx63aAhVIQ48
KHcjXBh4Q_AUICigB#imgrc=WefTF8Em01uZjM:

16. Systematic Position – Tilletia caries
Kingdom : Fungi
Phylum : Basidiomycota
Class : Exobasidiomycetes
Subclass : Exobasidiomycetidae
Order : Tilletiales
Family : Tilletiaceae
Genus : Tilletia
Species : T. caries

17. Systematic Position – Tilletia foetida
Kingdom : Fungi
Phylum : Basidiomycota
Class : Exobasidiomycetes
Subclass : Exoxobasidiomycetidae
Order : Tilletiales
Family : Tilletiaceae
Genus : Tilletia
Species : T. foetida

18. Systematic Position – Tilletia controversa
Kingdom : Fungi
Phylum : Basidiomycota
Class : Exobasidiomycetes
Subclass : Exobasidiomycetidae
Order : Tilletiales
Family : Tilletiaceae
Genus : Tilletia
Species : T. controversa

19. Life Cycle
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomyc
etes/Pages/StinkingSmut.aspx.

20. • These two smut fungi survive between growing
seasons as teliospores on the surface of healthy seed
or in the soil.
• They can remain viable in either location for a
number of years, perhaps ten years or more,
particularly if the spores remain dry on the seed
surface.

21. • When environmental conditions are favorable, each
teliospore germinates, producing sporidia.
• After compatible sporidia form the H-shaped
structure, the resulting dikaryotic, infectious hypha
penetrates a seedling.
• As the plant grows, the fungal hyphae also grow,
keeping pace with the apical meristerm.

22. H-shaped Sporidia.
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidio
mycetes/Pages/StinkingSmut.aspx.

23. • Eventually, the hyphae replace the cells of the seed, and
the individual cells of the smut fungus become
teliospores.
• During harvest, the smut spores are released from
infected heads as the heads pass through the combine
used to harvest the grain.
• They contaminate other seed being harvested or are
spread by the wind to the soil surface, later to be
incorporated into the soil mass during cultivation.

24. Life cycle of Tilletia controversa
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urce=lnms&tbm=isch&sa=X&ved=0ahUKEwjV6pXUx63aAhVIQ48KHcjXBh4
Q_AUICigB#imgr

25. Mode of Spread
Seed-borne - Spores can survive for 2 years.
Soil-borne - Spores can survive for several years.
Wind-borne
When the conditions are favored, they germinate
and cause infection.

26. Epidemology
• Cool temperatures (5-15°C/41-59°F) favor the germination of
the teliospores.
• Usually the soil moisture, which favors seed germination, also
favors spore germination.
• Sandy, humus rich soils favour infection.
• On the other hand, soils which are clayey and acidic are
detrimental to infection.
• Potassium and phosphatic fertilizers increase the severity of
infection.

27. Symptoms
Wheat plants
• Infected wheat plants are slightly shorter than healthy
plants.
• After heading, the spikelets of infected plants tend to
"flare-out" and take on a greasy, off-green color.
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/
Basidiomycetes/Pages/StinkingSmut.aspx

28. • In cultivars that normally produce long awns (bristle-like structures),
infected heads may have shorter awns, or even no awns .
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycetes/Pages/Stin
kingSmut.aspx

29. • In place of normal seeds, infected kernels develop
into "bunt balls”.
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomyc
etes/Pages/StinkingSmut.aspx.

30. • These are the remnants of what would normally be a
seed, but in its place, the seed coat remains intact
with the inside converted into a black mass of spores.
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidi
omycetes/Pages/StinkingSmut.aspx.

31. Wheat kernels
• The earliest evidence of infection occurs shortly after
ovaries would normally be pollinated.
• Infected ovaries appear greasy with a dark green
cast. When squeezed, such ovaries reveal a mass of
black spores that smell like rotting fish.
• This odor is actually that of trimethylamine, which is
produced by the smut fungus.

32. • As the heads and kernels mature, the bunt balls
develop into a hardened mass that looks like
miniature footballs.
• The spores inside the mature bunt balls are released
when the heads go through the combine harvester to
produce the cloud of dust.

33. • This dust also smells of rotting fish. Occasionally, both
healthy seeds and bunt balls are found in the same head.
©https://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycetes/Pa
ges/StinkingSmut.aspx.

34. Symptoms – Dwarf Bunt
• Disease symptoms can be evident after early spring
growth. Infected plants produce an abnormally high
number of tillers.
• After heading, sori similar to those described for
common bunt form instead of kernels.
• Sori of dwarf bunt are usually more rounded than
those of common bunt, giving the spike a ragged
appearance.

35. • It is common for infection to occur in only a few
spikes per plant and also in only a portion of the
kernels of individual spikes.
• Usually kernels are completely transformed into
teliospores, but partially diseased kernels can occur.
• This symptom can also occur in kernels infected with
common bunt.

36. ©https://www.google.co.in/search?q=dwarf+bunt+of+wheat+images&dcr=
0&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjV6pXUx63aAhVIQ48
KHcjXBh4Q_AUICigB#imgrc=7OO3HIeH5uA7mM:

37. Integrated Disease Management
Cultural control
• Use pathogen-free seed.
• Grow the crop during high temperature period.
• Adopt shallow sowing.
• Grow resistant varieties like Kalyan Sona, S 227, PV
18, HD 2021, HD 4513 and HD 4519.

38. Chemical Method
• Treat the seeds with Carboxin (Vitavox) or Carbendazim
(Bavistin) at 2g/kg.
• Captan, Manzate, Thiram, and Vitavax are registered but used
alone give only fair control of seedborne common bunt. All are
ineffective against soilborne common bunt.
• Triazole has been recommended against T.tritici at the rate of
19 µg/kg seed for seed-borne inoculum and 56 µg/kg seed for
soil borne inoculum.

39. • Difenoconazole seed treatment is recommended
against dwarf bunt.
• Tilt (0.01%) is highly effective as seed treatment
against the common bunt.

40. Biological Method
• Bacillus licheniformis, B. megaterium, B. pumilus
and B. subtilis are reported as antagonists of the bunt
pathogen in Australia.
• Pseudomonas fluorescens strain was reported to
provide control of common bunt (T. laevis) by
inhibition of teliospore germination.

41. • Hokeberg et al., (1997) had reported that a
strain of Pseudomonas isolated from roots and
applied as seed treatment strongly and reliably
suppressed common bunt (T. caries).