The document discusses bacterial and viral diseases affecting wheat, detailing several specific conditions such as yellow ear rot, black chaff, and bacterial leaf blight, as well as the wheat soil borne mosaic virus and wheat streak mosaic virus. Each disease is associated with particular pathogens, environmental conditions for optimal spread, and distinct symptoms affecting the wheat plants. The overall impact includes damage like distortion of earheads, discoloration of stems, and significant yield losses.

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.