sorghum diseas

2. S.
N
Diseas
es
Causal
organism
1 Anthracnose or Red leaf spot
2 Rust
3 Ergot or Sugary disease
4 Head Mould / Grain Mould / Head
Blight
5 Leaf Blight or Leaf Stripe
6 Grain Smut / Kernal Smut / Covered
Smut
/ Short Smut
7 Charcoal Rot / Hollow Stem / Stalk
Rot
Blight
8 Downy Mildewor Leaf Shredding
Colletotrichum graminicola
Pucciniapurpurea
Claviceps sorghi or
Sphacellia sorghi
Several Fungalgenera
Exserohilum turcicum or
Trichometasphaeria turcica
Syn: Helminthosporium
turcicumor
Drechslera turcicum
Sphacelotheca
sorghi
Sporisorium
sorghi
Macrophomina phaseolina

3. Symptom
s :
• Small red coloured spots on leaf.
• Whitish centre encircled by red, purple or brown margin.
• Numerous small black dots are seen on the white surface of the lesions
which are the fruiting bodies (acervuli) of the fungus, Many lesions
coalesce and kill large leaf portions.
• In midrib region, elongate elliptical, red or purple regions with black
acervuli
are formed
• Development of circular cankers on Stalk and inflorescence
• Infected stem when split open shows discoloration, which may be
continuous over a large area or more generally discontinuous giving the
stem a marbled
appearance.
Disease cycle
Primary
Infection
:
Collateral
host:
Secondary Infection
:
Fungus present in Seed, and IPD
Johnson grass, Sudan grass, maize, barley
and wheat
Wind born Conidia

4. Management
Destruction of infected plant debris and collateral hosts
Crop rotation with non-host crops
Grow resistant varieties like SPV 162, CSV 17, Texas Milo and Tift sudan
etc
Treat the seeds with Captan or Thiram @3 g/kg.
Spray the crop with Mancozeb @0.25% or carbendazim@0.1%

6. Symptoms
Small reddish brown flecks on the lower surface of the leaf
Pustules (uredosori) appear on both surfaces of leaf as purplish spots which rupture
to release reddish powdery masses of uredospores.
The pustules are elliptical and lie between and parallel with the leaf veins. Pustules
are surrounded by a reddish or yellow halo
Teliopores develop later sometimes in the old uredosori or in teliosori, which are
darker and longer than the uredosori
Puccinia purpurea
Disease cycle
Primary
Infection
:
Alternate
host
long cycled rust
Oxalis corniculata (aecial and pycnial
stage)
Secondary Infection
:
Wind born
uridospores

7. Favourable Conditions
Low temperature 10 to 120C
rainy weather
Management
Grow resistant varieties like CSH 5, SPV 13, 81, 126, PSH 1, CSV 17, etc.
Remove and destroy the alternate host Oxalis corniculata.
Spray the crop with Mancozeb @0.25%
Dusting of sulphur@25 kg/ha
Oxalis corniculata

9. Sympto
ms
 The disease is confined to individual spikelets.
 Secretion of honey dew (creamy sticky liquid) from infected florets. The honey
dew
secretion attracts large number of insects and ants which help in spreading the
disease.
 Often the honey dew is colonized by Cerebella sorghivulgaris which gives the head
a blackened appearance.
 Under favourable conditions, grain is replaced by long (1-2cm), straight or curved,
cream to
light brown, hard sclerotia.
 At the base of the affected plants white spots can be seen on the soil surface,
denoting the drops of honey dew which had fallen on the soil.
Disease cycle
Primary infection :
Secondary Infection :
Sclerotia germinates & produce ascospores
Air and insect born conidia & conidia also spreads
through Wind splash rain water
Favourable Conditions
1. High rainfall
2. High humidity during flowering
season.
3. Cool night temperature (20-25 0C)
4. Cloudy weather during anthesis

10. Management
Adjust the date of sowing so that the crop does not flower during the periods
of high rainfall and high humidity.
Grow resistant varieties like SPV 191, CSH 5, SPH 1 and CS3541.
Deep summer ploughing
Soaking seeds with 2% saline solution will aid to remove ergot infested seeds, as
ergot
infested seeds will float in the salt solution.
Seed treatment with fungicides such as Captan or Thiram@4g/kgseed
Spray Ziram (or) Zineb (or) Captan (or) Mancozeb @0.2% at emergence of earhead
(5-10 per cent flowering stage) followed by a spray at 50 per cent flowering and
repeat the spray after a week, if necessary.
Control of ergot with fungicides such as Propiconazole or Tebuconazole has proved
tobe
cost effective in seed production plots.

12. Symptoms
If rains occur during the flowering and grain filling stages, severe grain moulding can
occur. Infected grains are covered with pink or black mold and such grains
disintegrate during threshing process. Fusarium semitectum and F.moniliforme
develop a fluffy white or pinkish colouration. C. lunata colours the grain black. Fungi
from many genera have been isolated from the infected sorghum grains and the most
frequently occurring genera are Fusarium, Curvularia, Alternaria, Aspergillus,
Cheatomium, Rhizopus, Helminthosporium and Phoma. Moldy grains contain toxic
mycotoxins and are unfit for human consumption and cattle feed.
Disease cycle
• The fungi mainly spread through air-borne conidia. The fungi survive as parasites as
well as
saprophytes in the infected plant debris.
Favourable Conditions
• Wet weather following the flowering favours grain mould development and the longer
the wet period the greater the mould development. Compact ear heads are highly
susceptible.

13. Manageme
nt
Adjust the sowing time
Grow resistant varieties like GMRP 4, GMRP 9, GMRP 13 and tolerant varieties
like CSV 15.
Seed disinfestation with Thiram@0.3% will prevent seedling infection.
Spray Mancozeb (0.25%) or captan (0.2%) or captan 2g + Aureofungin 200ppm
per liter, in case of intermittent rainfall during earhead emergence, a week later
and during milky stage.

15. Leaf blight or leaf stripe Exserohilum turcicum or
Trichometasphaeria turcica
(Syn : Helminthosporium turcicum or Drechslera turcicum)
Symptoms
The leaf blight pathogen also causes seed rot and seedling blight of sorghum.
Small narrow elongated spindle shaped spots in the initial stage.
Later they extend along the length of the leaf becoming bigger.
On older plants - Long elliptical necrotic lesions, straw coloured in the
centre with dark margins.
Many lesions coalesce on the leaves, destroying large areas of leaf tissue
giving the crop a distinctly burnt appearance leading to premature drying of leaves.
Fungus present in Seed, Soil and
IPD
Seed or Wind born Conidia
Disease cycle
Primary Infection :
Secondary
Infection :
Favourable
Conditions
• Cool moist weather,
• High humidity (90
%)
• High rainfall

16. Use disease free seeds.
Crop Rotation with non susceptible crops
Collect and destroy IPD
Seed Treatment with Captan or Thiram at 4 g/kg.
Spray the crop with Mancozeb@0.25% at the age of 40 days and the spraying
have to be repeated twice at 15 days interval
Tift-Sudan is resistant to this disease

18. Symptoms
 The disease appears at the time of grain formation in the ear.
 The individual grains are replaced by smut sori (dirty white to gray ) and are
covered with a tough white cream to light brown skin (peridium).
 The glumes are unaltered and may be found adhering to the sides of the sorus.
 Sometimes the stamens may develop normally protruding out of the sorus.
 Ratoon crops exhibit higher incidence of disease.
Disease cycle
Primary Infection
: Secondary
Infection
Externally seed borne and
systemic Wind born Sporidia

19. Use disease free seeds.
Grow resistant varieties like T 29/1, PJ 7K, PJ 23K, Nandyal and
Bilichigan.
Treat the seed with fine sulphur powder @0.5% or Captan or Thiram
@0.3%.
Follow crop rotation.
Collect the smutted ear heads in cloth bags and dip in boiling water.

21. Charcoal rot or hollow stem or stalk rot blight
Favourable conditions
 Soil temperature 35 0 C
 Moisture stress conditions preceding crop maturity
 High dose of nitrogenous fertilizers
Primary
Infection
: sclerotial bodies present in the Soil, IPD,
Weed Host
Secondary Infection
:
sclerotial bodies carried through Rain or
irrigated water
Macr ophomina phase olina
Symptoms
Sudden Wilting and Death of the diseased plant resulting in Lodging.
If the infected stalk is split open, the pith is disintegrated with longitudinal
shredding of the tissue into fibers. Small black sclerotial bodies are seen in the
infected tissues.
The stem, breaks near the ground level. Premature ripening takes place and the
heads are poorly developed.
Disease cycle

22.  Thin plant population (60,000 plants/ha)
 Collected and burning of infected plants along with trash
 Avoid moisture stress at flowering
 Grow resistant varieties like E-36-1, CSV 5, CSH 7-R, SPV 126
and SPV 193.
Manageme
nt

24. Symptoms
Downy whitish growth is produced on the lower surface of the leaves.
White streaks appear on both the surfaces of the leaves.
The tissues then tear along the streaks causing Leaf shredding of the leaves. The
tissue then turns brown in colour. Numerous oospores are found in the shredded
leaves.
The affected parts are stunted and sterile.
Disease cycle
Primary Infection
:
Secondary
Infection:
Oospores present in the
Soil. mycelium , seeds
air-borne sporangia.
Favourable Conditions
Relative humidity 100 %
Optimum temperature 21-23 0
C
Light drizzling
Cool weather

25. Destroyal of affected plants by burning before oospore formation,
reduce
the inoculum potential
Crop rotation with other crops like pulses and oilseeds.
Grow Tolerant varieties like CSH 2, CSV 5, SPV 101, 165 and 190.
Seed Treatment with Metalaxyl (Apron 35 SD) @4g/kg seed
Spray Metalaxyl (Ridomyl MZ) @0.2% or Mancozeb @0.25%
M a na ge m e
nt

27. Disease
cycle Seeds present in the
Soil.
Primary Infection
: Secondary
Infection :
Favourable
Conditions
 Soil temperature350 C
Phanerogamic parasite (Strig a or Witc h Weed )
Striga asiatica , Striga densiflora
Symptoms
 Sorghum root exudates stimulate the seeds of the parasite to germinate.
 Parasite attach to the Host root by haustoria and grow below the soil surface
and produce
underground stems and roots for about 1-2 months.
 The parasite grows faster and appears at the base of the plant.
 Severe infestation
causes
Yellowing and wilting of the host
leaves. Stunted growth and may
die prior to seed setting, if the
infection occurs early

28. 1. Hand weeding of the parasites before
flowering.
n the absence of
host.
2. Crop rotation with cowpea, groundnut and sunflower.
3. Mixing of Ethrel with soil triggers germination of Striga i
4. Spray Fernoxone (sodium salt of 2,4-D) or Agroxone (MCPA) at
450g/500 liters of water or Praquat @ 1 kg/ha.
5. 1% Tetrachloro dimethyl phenoxy acetate can be used for instant
killing of Striga, if water is in scarce.
Tetrachloro dimethyl phenoxy acetate