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1. WELCOME……

2. Bacterial and viral diseases of
Wheat
Nagendra,S.R.
ALB2100

3. Contents
Bacterial Diseases
 Yellow Ear Rot
 Black
chaff/Bacterial
streak
 Bacterial leaf
blight
Viral DiseaseS
Wheat Soil borne
Mosaic virus
 Wheat streak
Mosaic Virus

4. 1)Yellow Ear Rot /
Tundu Disease
Pathogen: Clavibacter tritici (the disease is
known to occur only in association with
nematode ( Anguina tritici )
 The bacterium is spherical , gram positive and
capsulated.
 SPREAD: Seeds contaminated with nematode
galls are responsible for the spread of the
disease.

5. The disease is characterized by twisting, distortion
of earhead and
 rotting of spikelet's, with profuse oozing of yellow
liquid from the infected tissues.
Symptoms

6. 2)Black chaff = bacterial streak
• Pathogen: Xanthomonas translucence pv.
undulosum
•Favorable Environmental
Conditions:
Black chaff is favored by wet and humid
weather.

7. Symptoms:
 Discoloration of
glumes on a
mature white
head
Dark purple
discoloration of
wheat stem

8. BACTERIAL LEAF BLIGHT
• Pathogen: Pseudomonas syringae pv. syringae
• Favourable conditions : Moist and mild
weather during flag leaf emergence.
• It can tolerate warm or freezing
temperature.
• Free moisture is required for disease
development.

9. Symptoms:
 Start as narrow chlorate lesions on leaves, turn yellow
and then dark brown
When moist, a water soaked appearance from the
bacterial exudate I.e. sticky yellowish colors.

10. VIRAL DISEASES:
Wheat Soil borne Mosaic Virus
Wheat Streak Mosaic Virus

11. 1)Wheat soil borne mosaic virus
• Pathogen: Wheat yellow mosaic virus
(WYMV)
• Conditions: Long periods of fluctuating
temperatures in early spring.
• Transmission: Soilborne fungal vector
(Polymyxa graminis) and sap
transmission

12. Polymyxa graminis,is the reported vector of
wheat soil borne mosaic virus is an obligate root
parasite of wheat.

13. Symptoms:
Yellow green
mosaic on young
leaves, stunting,
severe rosetting
and excessive
tillering.
This virus is
transmitted by soil
borne fungi.

14. 2)Wheat streak Mosaic Virus
Transmission: Eriophes tulipae(Wheat
curl mite)
Alternate hosts: Maize, oats, barley, wild grass

15. Mosaic streaking
all along the veins,
the infested plants
produce fewer or
less tillering and
stunted growth.
Symptoms:

16. • Infects both winter and
spring wheat.
• Earlier infection =
greater yield loss.
• Grassy weeds, volunteer
wheat, corn, etc. can
harbor both WSMV and
the mite vector.