CAUSAL ORGANISM,SYMPTOM,MANAGEMENT

1. P PAT – 302 DISEASES OF FIELD CROPS AND THEIR
MANAGEMENT (1+1)
ASSIGNMENT TOPIC
KARNAL BUNT OF WHEAT
SUBMITTED BY, COURSE TEACHER
DEEPTHI.S, Dr. PARTHASARATHY.S,
2015021027. Asst. Prof., PLANT
PATHOLOGY

2. CAUSAL ORGANISM:
• Tilletia indica Mitra (Telomorphic stage).
• Initially, the disease was reported as
Neovassia indica (Mitra) Mundkur in 1940
then it was called as Tilletia indica Mitra in
1953.

3. NAME OF THE DISEASE
• International Common Names
English: Indian bunt of wheat; new bunt;
partial bunt of wheat.
French: carie de Karnal.
• Local Common Names
Germany: Indischer Weizenbrand.

4. • The disease is sometimes called partial bunt
because only part of the kernel usually is
affected.
• The infected grain gives decaying fish smell
due to trimethylamine.

5. HISTORY
• The first report of a new bunt disease in wheat
came from the region of Faizalabad (Pakistan)
in 1909.
• This was presumably Karnal bunt, which was
first formally recorded in 1930 near the north
Indian city of Karnal (Mitra, 1931). Within
India the pathogen spread and can now be
considered widespread in northern and central
India.

6. SYSTEMATIC POSITION
Domain: Eukaryota
Kingdom: Fungi
Phylum: Basidiomycota
Subphylum: Ustilaginomycotina
Class: Ustilaginomycetes
Subclass: Exobasidiomycetidae
Order: Tilletiales
Family: Tilletiaceae
Genus: Tilletia
Species: Tilletia indica

7. MODE OF INFECTION
• Primary spread of disease–The leaves
of monocotyledons appeared to support
sporidial survival.
• Secondary spread of infection - Seed borne
and soil borne disease.

8. FAVOURABLE CONDITIONS
• High humidity favours this disease.
• Temperature ranges from (8 - 23°C)
• Frequent rainfall favours disease
development.
• High dose of nitrogen.
• Close planting favours pathogen attack.

9. OCCURENCE IN WORLD
 Asia
Africa
 North and South America
Europe

10. OCCURRENCE IN INDIA
• Uttar Pradesh
• Haryana
• Punjab
• Himachal Pradesh
• Rajasthan and
• Madhya Pradesh.

11. SYMPTOMS
• The fungus causes a reduction in the length of
ears as well as in the number of spikelets of
bunted ears.
• Infected plants may be dwarfed.
• In general, T. indica rarely infects more than a
few spikelets per ear and then the affected grains
are not swollen.

12. • Oblong or ovoid sori, 1-3 mm diameter,
develop, containing dusty, brown to black
spore masses.
• The smell of decaying fish on grains.
• In advanced attack, tissues along the suture
and adjacent endosperm are replaced by
spores. Both glumes and grains may fall to the
ground.

13. SYMPTOMS
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14. SYMPTOMS
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15. PATHOGEN CHARACTER
Teliospores are dark reddish to coppery, dull
brown or dark brown, some spores typically
black/opaque, globose to subglobose.
Occasionally with a mycelial fragment
attached,24-47µm diameter exospore with thick,
truncate, compact projections.

16. symptoms
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17. TELIOSPORE OF Tilletia indica
© https:www.cals.ncsc.edu

18. ©https:www.cals.ncsc.edu

19. ECONOMIC IMPORTANCE
The disease appeared in the Punjab (India)
around 1930. It was epidemic there in 1953-1954.
 Until 1970, sporadic outbreaks occurred every 2-
3 years in the Punjab, Haryana and Uttar Pradesh
regions, with a disease incidence of 0.1-10%.
 Annual yield losses of about 0.2% .

20. In 1974 and 1975, the disease was epidemic in
other regions (Himachal Pradesh, Tarai areas
of Uttar Pradesh and the Gurudaspur area of
the Punjab) with 50% infection on the cultivar
HD-2000.
 In Mexico, where Karnal bunt appears
regularly, direct losses are not very significant
and do not exceed 1%.

21. LIFE CYCLE
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22. IDM:
CULTURAL PRACTICES:
Grow resistant varieties such as HD 1907, L
176, HI 358, HP 743 and L 191.
Crop rotation may help to control the pathogen,
because T. indica can survive for up to 4 years
in the soil.
The movement of farm machinery from
contaminated fields may also be restricted.

23. To prevent the spread of T. indica into
previously unaffected areas, the use of disease-
free seed is essential.
Deep ploughing is done to remove spores.
Split application of Nitrogen fertilizer reduces
the incidence of the disease.

24. CHEMICAL CONTROL
Chemical seed treatments have proved to be
ineffective in killing the teliospores of
T. indica on seeds of wheat, with the exception
of mercurial compounds, which are banned in
most countries.
 Bleach, in combination with heat treatment, is
effective(Soaking at 35°C for 12 h was the most
effective treatment).

25. Carboxin + thiram and Chlorothalonil have
been used as seed treatments in the USA and
Mexico.
Foliar spray of Propiconazole was shown to be
effective against natural infection in India.
Apply Cyproconazole @ 500 ml/ha and
Bavistin @ 1000g/ha may be recommended.

26. BIOLOGICAL CONTROL
• Leaf extract of Azadiracta indica and Cassia
fistula used as spray.
• Seed treatment with Thiram or Carbendazim
2g/kg makes the seed free from seed borne
pathogen.
• Foliar spray of conidial suspension of
Trichoderma viridae or T. harzianum @
5ml/ha.