Wheat Rust.pdf by Anil dhayal SKN jobner

Wheat rust disease

1. Rusts of Wheat

2. ➢Rust: Rust means rusty appearance on plant parts & caused by rust fungi
belonging to order Uredinales (Rust Fungi) in Basidiomycota.
➢Ancient Romans prayed Rust God- “Robigus” at a ceremony “Robigalia”
(a festival) to save crop from the disease. Ceremony involved a procession,
followed by sacrifice of reddish (or yellow) colored animals (such as dogs
or cows).
➢Father of Indian Rust: Dr. K. C. Mehta (Karam Chand Mehta) of Agra
college.
IMPORTANT GENERAL POINTS ABOUT RUST

3. ➢Rust epidemics occurred in India are as follows:-
(i) In 1827 in M.P.
(ii) In 1946-47 in MP, MH, Raj, UP.
(iii) In 1956-57 in WB, Bihar, UP. (In Bihar yield was only 50 kg/ha in 1957).
(iv) In 1972-73 in WB, HR, UP. In Raj. in Sanchor (Jalore) around 1974.
➢Rust fungi are “obligate (Biotroph) parasites”
➢Wheat is affected by 3 different types of rust diseases:-
(i) Black or stem rust by Puccinia graminis var. tritici (UG-99 race).
(ii) Brown or leaf rust (orange rust) by Puccinia recondita.
(iii) Yellow or stripe rust by Puccinia striiformis.

4. ➢Wheat rust fungi produce 5 different “Fruiting structures” with 5 different “spore
forms” that appear in a definite sequence (Trick for memory: spore sequence is PAUTB
or Now SAUTB).
Sequence Name of spore Fruiting body
P (S) Pycniospores (Spermatia)Pycnidia (Spermogonia)
A Aeciosopres. Aecia
U Urediospores Uredia
T Teliospores Telia
B Basidiospores Basidia

5. ➢Brown & yellow rusts cause more damage than black rust (because black rust appears late
i.e. in March- April in north India.
➢“Uredospores” are called “Repeating Spores”. Because they infect wheat in same season
again & again.
➢“Teliospores” are called “Resting Spores” or winter spores in which karyogamy takes place
(n+n = 2 n).
➢“Basidiospores” infect “Barberry leaves” (alternate host).
➢“Aeciospores” infect “wheat’’ through stomata (in countries where barberry bushes
present).
➢Wheat rust fungus is “Heteroecious” in nature (i.e. fungus complete their life cycle on two
different hosts (wheat & barberry).
➢In India, the most common & most damaging rust is “Brown Rust”.

6. ➢“UG-99”: A fast spreading race originated in Uganda in 1999 (So called Ug-99).
➢Alternate hosts are Berberis & Mahonia (but not functional in India).
BLACK RUST OF WHEAT
Danger: UG-99: Race of Black rust: From Uganda in 1999: No resistant to it: No control measures.

7. (A) On wheat:-
➢ The stems are most severely attacked (so called stem rust).
➢In India, the symptoms first noticed in plains (major wheat growing area) late in season i.e.
in March-April (so called late rust).
➢Long brown pustules of uredia appear on the stem, sheath & leaves, which give a rusty
appearance.
➢The epidermis, covering these pustules gets ruptured & giving a powdery mass of brick red-
colored (i.e. rusty color) uredospores.
➢Later, the rust-colored uredo-pustules become black, the fungus produces teliospores in
black telia on stem. So called black stem rust.
➢The grains are shriveled & lighter in weight.
SYMPTOMS

8. (B) On Barberry: - (In countries where alternate hosts are functional).
➢ Yellowish or orange colored spots appear on leaf. Later on, small dark
bodies (spermogonia) appear within such spots.
➢On lower side of leaf, orange, cup-like aecia appear in group. Aeciospores
causes infection on wheat plants (The main host).

9. PATHOGEN:- Puccinia graminis var. tritici
Classification according to Hawksworth et al. (1995):
Kingdom -Fungi
Phylum - Basidiomycota
Class –Teliomycetes
Order -Uredinales (The rust fungi)
Family - Puccinaceae
Genus - Puccinia
Species - graminis var. tritici

10. ➢This pathogen is a Macrocyclic (i.e. produces 5 spore types: SAUTB), Heteroecious (i.e.
completes life cycle on two different hosts: wheat & barberry and Obligate in nature.
➢Pycnial & aecial stages are produced on alternate hosts like Berberis & Mahonia
whereas uredial & telial stages occur on wheat & grasses.
➢Uredospores are brown, oval (egg- shaped) with echinulated walls (small spines on
spore wall) and one-celled. Teliospores are spindle shaped, brown in colour, two-
celled with pointed apex.
➢Basidiospores are produced on promycelium of teliospores.

11. In Indian conditions, where functional alternate hosts are not found.
Survival: It survives in the form of uredial stage on self-sown or volunteer, summer wheat & grasses in
the hills.
➢The over-summering takes place in Himalayas in North India and in Nilgiri & Pulney hills in south
India.
➢The uredospores are spread by wind from hills to the plains (Major wheat growing areas).
➢The defined route/path of long distance dispersal from source to target (crop) is called “Puccinia
Path”. In India, Berberis do not occur in the Plains.
➢In the hills, less susceptible species of Berberis are found but Puccinia graminis var. tritici is not
able to infect.
➢Uredial stage also survives on collateral hosts like Aegilops sp., Bromos, Hordeum murinum,
Lolium etc. on hills.
DISEASE CYCLE

12. (ii) Primary infection: The uredospores carried to the plains of India from hills by air
currents (i.e. Puccinia Path ) work as the source of primary infection.
(iii) Secondary infection: The uredospores produced as a result of primary infection
serve as the main source of secondary infection during the same growing season.
Because, the production of Uredospores are repeated again & again & causes many
secondary infection cycles (Polycyclic disease) during one growing season, that’s why
uredospores are also called “Repeating spores”.

13. (iv) Pre-disposing factors:- (a) It is favored by hot days (25-30
0
C).
(b) Mild nights (15-20
0
C) and
(c) Wet leaves from rain or dew, since uredospores require free water for germination to cause infection.
MANAGEMENT :-
(A) CULTURAL PRACTICES:-
(i) Use early maturing cultivars.
(ii) Avoid excessive use of nitrogenous fertilizes.
(iii) Adopt mixed cropping with gram, mustard etc.
(iv) Destroy collateral/alternate (wherever these are functional).
(v) Destroy volunteer or self sown wheat plants several weeks before sowing.

14. (B) CHEMICAL CONTROL:-
(i) Spray zineb or mancozeb (0.2%) or propiconazole (Tilt = 0.1%) or oxycarboxin (Plantvax).
(ii) Dusting with sulphur dust @ 25 kg/ha at an interval of 4 days.
(iii) Use of film forming or anti-transpirant compounds like Bio Film (0.5%), Foli Cote, Vapor Gard.
These interfere with site of infection on leaves (stomata).
(C) RESISTANT VAR: The most effective mean of rust control is use of resistant var.
(i) Use resistant var. like-PBW – 343, HD-2278, HW- 741, Choti Lerma, Sonora –63 etc.

Mostly, the resistant cultivars used in India contain the “Sr-31 gene” which unfortunately is susceptible
to the fast-spreading “UG-99 race” of the pathogen. It may soon enter South Asia, & knock at our door.
The wheat breeders have been alerted by G.R.I (Global Rust Initiative) regarding the need for developing
cultivars resistant to the UG-99.

15. ➢It is also called “Orange rust or Leaf rust’.’
➢This is the most common rust in North & South India.
➢It appears earlier than the black rust (i.e. in Jan.).
BROWN RUST OF WHEAT

16. SYMPTOMS:-
➢ The color of pustules in beginning is bright orange, but later it becomes
brown (that’s why it is called brown rust).
➢The pustules are scattered mainly on the upper surface of leaves (so called
leaf rust), rarely on the leaf sheaths or stem.
➢Telia are produced under epidermis & it does not rupture & the teliospores
not exposed.

17. PATHOGEN: Puccinia recondita (Now P. triticina)
Classification according to Hawksworth et al. (1995):
Kingdom -Fungi
Phylum - Basidiomycota
Class –Teliomycetes
Order -Uredinales (The rust fungi)
Family - Puccinaceae
Genus - Puccinia
Species - recondita

18. ➢ It is also a macrocyclic, heteroecious & obligate in nature.
➢The uredospores are spherical (round) and brown with minutely
echinulated walls.
➢The teliospores are two-celled, smooth & brown with round or
conical apex.

19. DISEASE CYCLE:
In Indian conditions, where functional alternate hosts are not found.
(i) Survival: It has two sources of inoculums i.e. Nilgiri & Pulney hills in South
India & Himalayas in North India on self sown or volunteer wheat plants in hills
as uredial stage. Uredospores blown down from hills to plains with air. Alternate
hosts like Thalictrum found in hills but non- functional. Uredial stage also survive
on collateral hosts like Aegilops sp. on hills.
(ii) Primary infection: The uredospores carried to the plains of India from hills by
air currents (i.e. Puccinia Path) work as the source of primary infection.

20. (iii) Secondary infection: The uredospores produced as a result of primary
infection serve as the main source of secondary infection during the same
growing season. Because, the production of Uredospores are repeated
again & again & causes many secondary infection cycles (Polycyclic
disease) during one growing season, that’s why uredospores are also
called “Repeating spores”.
(iv) Pre-disposing factors:-
(a) Favorable temperature is 20
0C.
(b) Wet leaves from rain or dew, since uredospores require free water for
germination to cause infection.

21. MANAGEMENT :-
(A) CULTURAL PRACTICES:-
(i) Use early maturing cultivars.
(ii) Avoid excessive use of nitrogenous fertilizes.
(iii) Adopt mixed cropping with gram, mustard etc.
(iv) Destroy collateral/alternate (wherever these are functional).
(v) Destroy volunteer or self sown wheat plants several weeks before sowing.
(B) CHEMICAL CONTROL:-
(i) Spray zineb or mancozeb (0.2%) or propiconazole (Tilt = 0.1%) or oxycarboxin (Plantvax).
(ii) Dusting with sulphur dust @ 25 kg/ha at an interval of 4 days.
(iii) Use of film forming or anti-transpirant compounds like Bio Film (0.5%), Foli Cote, Vapor Gard. These
interfere with site of infection on leaves (stomata).
(C) RESISTANT VAR: The most effective mean of rust control is use of resistant var.
(i) Use resistant var. like-PBW – 343, 373, 425, HD-2687, HW- 741, 2044, 2045, Raj. 3765.

22. ➢It is also called “stripe rust” of wheat.
➢It appears mainly in North & northwest India.
➢It appears earlier than other rusts, so also called “Early
rust” (in Dec-Jan in plains).
YELLOW RUST OF WHEAT

23. SYMPTOMS:-
➢ Bright yellow, pin-head sized uredia are arranged in long rows (end
to end forming stripes) on the leaves.
➢This gives the name “yellow” & “stripe” rust to the disease. In
severe infections, all parts are infected, & the stripes disappear due
to the crowding of uredia.
➢Telia appear at the end of the season as black stripes on the lower
surface of leaves.

24. PATHOGEN: - Puccinia striiformis.
Classification according to Hawksworth et al. (1995):
Kingdom -Fungi
Phylum - Basidiomycota
Class –Teliomycetes
Order -Uredinales (The rust fungi)
Family - Puccinaceae
Genus - Puccinia
Species - striiformis

25. ➢ It is heteroecious & obligate in nature.
➢The uredospores are nearly round, yellow & with minutely echinulated
wall.
➢Teliospores are dark brown with flattened tip or apex & bi-celled.

26. DISEASE CYCLE:-
(i) Survival: - It survives in hills on volunteer plants or summer crop in the
form of uredospores. Many collateral hosts also provide inoculum in hills
like –Bromus, Agropyron, Hordeum murinum etc. but alternate host is not
still known.
(ii) Primary infection: The uredospores carried to the plains of India from
hills by air currents (i.e. Puccinia Path) work as the source of primary
infection.

27. (iii) Secondary infection: The uredospores produced as a result of primary
infection serve as the main source of secondary infection during the same
growing season. Because, the production of Uredospores are repeated
again & again & causes many secondary infection cycles (Polycyclic
disease) during one growing season, that’s why uredospores are also
called “Repeating spores”.
(iv) Pre-disposing factors:-
(a) Favored by low temperature (10-15
0
C).
(b) Wet leaves from rain or dew, since uredospores require free water for
germination to cause infection.

28. MANAGEMENT :-
(A) CULTURAL PRACTICES:-
(i) Use early maturing cultivars.
(ii) Avoid excessive use of nitrogenous fertilizes.
(iii) Adopt mixed cropping with gram, mustard etc.
(iv) Destroy collateral/alternate (wherever these are functional).
(v) Destroy volunteer or self sown wheat plants several weeks before sowing.
(B) CHEMICAL CONTROL:-
(i) Spray zineb or mancozeb (0.2%) or propiconazole (Tilt = 0.1%) or oxycarboxin (Plantvax).
(ii) Dusting with sulphur dust @ 25 kg/ha at an interval of 4 days.
(iii) Use of film forming or anti-transpirant compounds like Bio Film (0.5%), Foli Cote, Vapor Gard. These
interfere with site of infection on leaves (stomata).
(C) RESISTANT VAR: The most effective mean of rust control is use of resistant var.
(i) Use resistant var. like-PBW – 343, 373, 425, HD-2687, HW- 741, 2044, 2045, Raj. 3765.

29. S NoParameter Black rust Brown rust Yellow rust
1 Pathogen Puccinia graminis var.
tritici
Puccinia recondita Puccinia striiformis
2 Suitable
temperature range
25
0
C 20
0
C 10-15
0
C
3 Time of
appearance in
plains
In Mar- April
(Late rust)
Crop near maturity: Not
too loss.
In Jan. In Dec-Jan.
(Early rust)
4 Most attacked part
of plant
Stems than leaves &
ears.
Leaves. Leaves than sheaths, stems
& ears.
5 Uredia or
Uredopustules
Rust-red colored.
Large & long.
Brown colored.
Small & round.
Yellow colored.
Small i.e. pin head size
arranged in rows.
Comparison between three rusts of wheat:

30. 6Uredospores
(Repeating spore
(n+n))
Oval shaped.
Brown colored.
Echinulated.
One –celled
Round shaped.
Brown colored.
Echinulated.
One –celled
Round shaped. Yellow
colored or brown.
Echinulated
One –celled
7Telia or
teliopustules
Black in color.
Burst earlier.
On all parts.
Rarely present, if so dull
black, not burst.
Dull black.
Not burst.
8Teliospores
(Resting spore )
(n+n)
Spindle shaped.
Two –celled.
Dark brown.
Pointed apex.
Two -celled.
Brown colored.
Rounded apex or conical.
Two- celled.
Dark-brown.
Flattened at top.
9Pycnia & aeciaFormed on alternate
hosts
Formed on alternate hostsThese stages are not
reported
10Alternate hostBerberis
Mahonia
Thalictrum
Isopyrum
Not Known

31. 11Collateral hostsBromus, Aegilops,
Lolium, Hordeum
murinum
Aegilops sp. Muhlenbergia hugelli (in
Shimla hills, a grass),
Bromus, Hordeum
murinum
12No. of races &
biotypes known in
world
250 (34 in India) 100 (30 in India) 50 (23 in India)
13Annual recurrence
in India
By uredospores from
hills with air
By uredospores from hills
with air
By uredospores from hills
with air
14Major source of
primary inoculum
come from
From hills of
South India (Nilgiri &
Pulney hills).
From hills of North & South
India.
(Himalaya in North & Nilgiri
& Pulney hills in South India ),
so more dangerous, because
it cover large area within
short period of time in entire
India.
From hills of
South India (Himalaya hills
in N. India)

32. Puccinia produces 5-spore types, numbered 0-IV (in Roman numerals) on two different hosts as follows:
Stage Spore types produced
(PAU TB)
Name of fruiting body in/on spore
produced
Nuclear status
of spore &
mycelium
Host on which spore
produced
Singular Plural
Stage -0Pycniospores
(Now spermatia)
Pycnium
(Spermogonium)
Pycnia
(Spermogonia)
Monokaryotic
(n)
On Barberry
Stage-IAeciospores
(infect to wheat)
Aecium Aecia Dikaryotic
(n+n)
On Barberry
Stage-IIUrediospores /
Uredospores/
Urediniospores
(Repeating spores)
Uredium Uredia Dikaryotic
(n+n)
On wheat
Stage-IIITeliospores/Teleutospores
(Resting spores)
Telium Telia Dikaryotic
(n+n)
On wheat
Stage-IVBasidiospores (sexual spore)
(infect barberry)
Basidium Basidia Monokaryotic
(n)
Wheat stubbles (inactive
substrate) wheat debris