2. UNIVERSITY OF AGRICULTURAL SCIENCES
PAT.301(2+1)
DISEASES OF FIELD CROPS AND
MANAGEMENT
TOPIC:FUNGAL DISEASES OF WHEAT
BY,
NAGENDRA
ALB2099
3. FUNGAL diseases of WHEAT
Major Fungal disease in wheat……….
1. RUSTS
A. Stem rust
B. Leaf rust
C. Stripe rust
2. LOOSE SMUT
3. KARNAL BUNT
4. POWDERY MILDEW
5. FOOT ROT
6. LEAF BLIGHT
4. Rusts
– Three forms rusts can affect wheat (all fungal
forms)
Stem rust
Leaf rust
Stripe rust
5. • BLACK or STEM RUST
Pathogen: Puccinia
graminis tritici
Uredospores are brown
and oval
Each cell of teleutospore
has one pore
Size is about 25-30x15-
20µm
6. • SYMPTOMS:
Reddish brown pustules
The large number of
uredosori burst, release
their spores
Infected parts bursting to
expose a mass of brown
uredospores
Brownish appearance even
from a distance
7. Favorable conditions
o Temperature: Between 23-25° C
o In this condition large number of teliospores are
produced.
Alternate hosts
Berberis,
Mahonia and
Mahoberberis
8. Leaf Rust (Brown or
Orange Rust)
Pathogen: Puccinia recondita
The pathogen is macrocyclic
rust.
Uredospores are brown and
spherical
16-28um in diameter
9. • SYMPTOMS:
The black telial pustules
are usually formed on the
dorsal side of leaves
The pustules burst early
with mild displacement of
the host epidermis
And deeply embedded into
the host.
10. Stripe Rust(yellow rust)
Caused by: Puccinia striiformis
Uredospores are spherical to
ovate in shape
Uredospores are orange
colored.
Size measuring from 23-35x20-
35µm
Teleutospores are dark brown
and flattened at the top when
in contact with the epidermis
11. Symptoms
appear early in the
spring.
Rust pustules are
yellow.
Spores are blown in
from warmer areas.
Disease
development is most
rapid under cool, wet
weather.
14. Loose smut of Wheat
Pathogen: Ustilago tritici(=U.
nuda tritici)
The teliospores are single
celled and formed irregularly
from fertile hyphae.
Teliospores are olivaceous
brown, spherical to oval
Measures 5-9µm in diameter
15. SYMPTOMS:
Can only be seen at the time
of flowering though the plants
are infected right after seed
germination.
Ears of infected one emerge
early than healthy one.
and transformed into black
powdery mass
Whole ear is covered by
delicate silvery membrane.
Resulting in formation of very
dark olive brown powdery mass
16. • Kernel bunt
• Pathogen: Neovassia indica
Spores are smooth walled
Measuring 22-49µm in
diameter
Requires long rusting period
The primary sporadia are
needle shaped and flexible
The secondary sporadia are
sickle shaped
17. • SYMPTOMS:
Plants ripen early than the
healthy one
Ears are dark green
The glues are pushed apart
by the spore balls which
are formed instead of
kernels
18. • POWDERY MILDEW
• Pathogen: Erysiphe graminis
var. tritici
• The conidia are elliptical,
hyaline, single celled, thin
walled and produced in
chains
• Fungus produce septate,
superficial, hyaline mycelium
on leaf surface with short
conidiophores
19. • SYMPTOMS:
Greyish white powdery
growth appears on leaf,
sheath, stem and floral
parts
Powdery growth later
become black lesion and
Drying of leaves and
Other parts
20. Fungus remains infected in plant debris as dormant
mycelium
Favorable temperature is 20-21°C and High RH
21. • FOOT ROT
Pathogen: Pythium
graminicolum and P.
arrhenomanes
This fungus produces
sporangia, zoospores and
oospores.
22. • SYMPTOMS:
The disease mainly occurs
in seedlings
Roots and rootlets become
brown in color
Seedlings becomes pale
green and have stunted
growth
Wet weather and high
rainfall is favorable