EPIDEMIOLOGY AND MANAGEMENT

1. SIVAGNANAPAZHAM K
2018601508

5. FUNGAL DISEASES
 POWDERY MILDEW-Erysiphe cichoracearum
 DOWNY MILDEW -Plasmopara halstedii
 RUST -Puccinia helianthi
 HEAD ROT -Rhizopus sp
 CHARCOAL ROT -Macrophomina phaseolina
 FUSARIUM ROOT ROT- Fusarium sp
 PHOMA BLACK STEM- Phoma macdonaldii
 PHOMOPSIS STEM CANKER- D.helianthi
 SCLEROTINIA STEM ROT/WILT-S.sclerotiorum
 VERTICILLIUM WILT -V.dahliae

6.  WHITE RUST – Albugo tragopogonis
 LEAF BLIGHT- Alternaria helianthi / zinniae
 SEPTORIA LEAF BLIGHT- S.helianthi
BACTERIAL DISEASES
 BACTERIAL HEAD ROT- Pectobacterium
carotovorum sub sp carotovorum
 APICAL CHLOROSIS- P. syringae pv. tagetis
 BACTERIAL LEAF SPOT- P. syringae pv.
helianthi

7. VIRAL DISEASES
 SUNFLOWER MOSAIC - Sunflower mosaic
virus.
 SUNFLOWER NECROSIS- Tobacco streak
virus.
 SUNFLOWER RING SPOT- SRV ( Illar virus).
PHANEROGAMIC PARASITE
 BROOM RAPE – Orobanche cumana

8.  Alternaria Leaf Blight
 Downy Mildew
 Rust
 Sclerotium Wilt and Collar Rot
 Charcoal Rot
 Sclerotinia Wilt and Rot Disease
 Powdery Mildew
 Head Rot
 Sunflower Necrosis Disease

9.  In areas of tropical and subtropical climates.
 Prevalent in Brazil.
 Damage - great reduction in photosynthetic area
of the plant.
 Severely attacked plants show early maturation,
with reduced production and seed weight.
 Seed yield by 27 to 80% and oil yield by 17 to
33%.
 Affects the seed germination and vigor of
seedlings.
(Leite et al., 2006).

10.  Young leaf spots are small, dark, angular Leaf
spots usually are found between major leaf
veins, along leaf margins and tips and will
coalesce.
 Extensive yellowing (chlorosis) occurs, followed
by browning and leaf death.
 Defoliation occurs from the ground up Stem
lesions are dark, narrow, elliptical and about ½
to 1½ inches long.

12.  Conidia are cylindrical to ellipsoidal.
 5 transverse septa, no tail, and are formed
singly in cylindrical conidiophores.
 Mycelium olive brown, septate, branched.
 Fungus grow slowly on PDA forming greyish
colonies.
 Also pathogenic to chrysanthemum
(Davet et al.,1991)

13.  Favorable conditions – produces large number
of conidia that are spread by rain and wind.
 Conidial germination – High RH & Temp - 25-
27° C temperature and 12 hrs of wet foliage.
 Optimum conditions for infection by A. helianthi
are leaf wetness for 24 h at 25°C
 The disease spreads rapidly in rainy season.
 Disease progresses rapidly from the lower
leaves to upper leaves.
(Leite & Amorim, 2002).

14.  The fungus overwinters as mycelium on infected
plant residues and in dry conditions survives for
20 weeks in soil
 The fungus is seed borne with 22.9% seed
transmissible nature.
 A.alternata infects only in Rabi season.
.

15.  Crop rotation for atleast four years.
 Destruction or removal of infected crop debris.
 Adjustment of sowing dates.
 Late sowing is favorable to high Alternaria
disease severity in sunflower crop
 Minimize the occurrence of disease, it should
avoid when the flowering coincides with periods
of heavy rain.
(Gadhave et al., 2011).

16.  Seed treatment with Carbendazim(12%) +
Mancozeb(63%) formulation @3g/kg seed.
Followed by two sprays of Propiconazole@
1ml/L at 45 and 60 DAS.
 Intercropping sunflower with groundnut in the
ratio of 6 : 2 reduces the disease incidence.
 Early planting of sunflower during kharif season
results in low occurrence of leaf blight.
 Spacing of 60 x 30 cm or 45 x 30.
( ICAR- IIOR-Hyderabad)

17.  Seed treatment with carbendazim+iprodione at
0.3% in water along with foliar spray of
hexaconazole was found most effective in
managing Alternaria blight.
 seed treatment with Pseudomonas fluorescens
(0.8%) in jelly+hexaconazole foliar spray.
(UAS Dharward)

18.  Temperate, tropical or subtropical climates
 Losses - the fungus, which can infect roots,
stem or sunflower head.
 Quickly kills the infected plants at seedling
stage, resulting in stand failures.
 Oil quality is lower due to seeds infected by the
fungus. (40DAS after sowing)
 Indirect losses occur due to contamination of
seeds with sclerotia.
 Persists in the soil for many years.
(Leite et al., 2000).

19.  Fungi develops internally and destroys the
internal tissues.
 Infection occurs on leaves wounds and
proceeds toward the petiole, ending the stem.
 Initial symptoms are characterized by light
brown and soft lesions on the dorsal side of the
head.
(Zimmer & Hoes, 1978)

20.  Basal rot may occur from the seedling stage to
maturity.
 Infection is mostly observed near flowering
 Rot starts when the mycelium originating from
sclerotia in the soil, comes in contact with the
lateral roots
 Sudden wilting of the plant.
 Infected plant - turgidity at night after a rainfall,
but within a few days this symptom becomes
irreversible, and the disease is named
Sclerotinia wilt

22.  Hyaline multicellular hyphae
 Sclerotium germination occurs in myceliogenic -
hyphae and carpogenic –apothecia
 Myceliogenic germination of sclerotia- root rot,
stem rot and wilting.
 The apothecium is a flat or cup-shaped structure
that produces sexual spores of S.sclerotiorum.
 Asexual – hyphae and sclerotia Sexual -
ascospore
(Mordue & Holliday, 1976)

23.  The fungus survives as sclerotia or mycelium in
infected plant residue and soil
 Secondary contamination is possible through
direct contact of the diseased tissue with healthy
tissue from neighboring plant
 Seeds - dissemination of S. sclerotiorum, as
sclerotia mixed with the seeds or fungus
mycelium colonizing the internal tissues
(Davet et al., 1991)

24.  High RH above 70% a mature apothecium can
produce up to 2 x 108 ascospores over a period
of several weeks.
 The ascospores are released at temperatures of
3ºC to 22ºC,with greater intensity between 19ºC
and 20ºC.
 Temperatures above 25ºC and relative humidity
below 35% are limiting for ascospore survival.
 Optimum temperature for development of the
mycelium is between 18ºC and 25ºC.
(Gulya et al., 1997)

25.  Crop rotation of 3-4 years helps to reduce
disease.
 Elimination of infected plant residue
 Deep ploughing of soil.
 Moisture stress and water logging conditions
should be avoided in the field
 Seed dressing with thiram + carboxin (2:1) at 3-
6 g/kg of seed is found to be effective control of
the seedling phase of the plant.

26.  Occurs in greater intensity in tropical areas
 In temperate areas, powdery mildew is usually
not observed until flowering and rarely has
economic importance
 In India, the disease was first reported in
Bombay (Patel et al., 1949)
Rajastan (Prasada et al., 1968),
West Bengal (Goswami and Dasgupta, 1981)
Punjab (Bains et al., 1996)
 Causing a significant yield reduction.

27.  White to grey powdery patches appear on upper
surface of older leaves which are still green.
 Occassionally the symptoms appear on stem
and bracts.
 White to grey areas enlarge, coalesce and cover
most plant parts.
 As the season progresses, the mildewed leaves
take on a dusty, powdery appearance.

28.  This powder is easily rubbed off. Small black
dots, cleistothecia become visible as black
pinpoints over the white mildew areas late in the
season.
 Severely infected areas lose luster, curls,
become permanently yellow and may dry up.
 Normally the lower leaves are more heavily
infected than the upper leaves
(Zimmer & Hoes, 1978; Almeida et al., 1981)

30.  Obligate parasite
 Mycelium is usually well developed.
 Spores are formed in long chains, have ellipsoid
shape and size ranging from 25-45 μm x 14-26
μm.
 Produces cleistotecia, which are black
structures responsible for survival of the
pathogen,containing asci with two ascospores
(Kapoor, 1967)

31.  Transmission is primarily through cleistotecia
that survive from one growing season to another
 Conidia can also survive
 Conidia are disseminated primarily by wind,
which can reach long distances
(Kapoor, 1967)

32.  Optimum conditions for infection are
temperatures around 25ºC and relative humidity
of 95%.
 Conidia do not germinate when there is a water
film on the leaf surface.
 Disease is favored by hot and dry periods
(Kapoor, 1967; Zimmer & Hoes, 1978)

34.  Fungicides azoxistrobin + ciproconazole and
difenoconazole are registered for control
powdery mildew in sunflower (Ministério,
2012)
 Clone, Aerosil, Kumulus and Sulfex Gold at
0.02% concentration effective
( Nagaraja, 2000, Singh et al., 2000)
 Application of wettable sulphur 0.2% or
karathane 0.2% or propiconazole 0.1% or
difenoconazole 0.05% three times at 15 days
interval effectively controls the disease.

35.  Spray propiconazole / Difenoconozole @ 1ml /L
at 45 and 60 DAS.
 Spraying wettable sulphur @ 3g/L or Calixin 1
ml/L is also effective reducing the disease
incidence.
(ICAR-IIOR – Hyderabad)

36.  The disease was recorded for the first time in
1984 in Latur and Beed districts of Marathwada
region of Maharashtra in India with an intensity
ranging from 5 to 60%.
 Later the disease has spread to other areas of
Maharashtra, Andhra Pradesh and Karnataka.
 The losses in yield were reported to be 2-25%.

37.  The fungus causes different types of symptoms
as damping off of seedlings, systemic
infection, Local foliar lesions and root galls.
 Damping off
 Symptoms appear as yellowing of the first pair
of true leaves.
 Under conditions of cool temperature and high
humidity, whitish growth of downy appear on the
cotyledonary leaves of young seedlings.

38.  As the plant grows, the fungus spreads to
younger tissue, the chlorotic area expands and
chlorosis appears on leaves and also on stem.
 Affected plants bear abnormally thick, downward
curled leaves showing prominent yellow and
green mottling.
 Stem – brittle & flower heads of the affected
plant - sterile, stiff and face upwards and seeds
are not produced.

39.  Increases -transpiration rate and respiration
 Decrease in level of carbohydrates and
accumulation of potassium and phosphorus in
leaves of infected sunflower plants.
 Foliar lesions
 Greenish yellow small angular spots appear on
leaves. The spots may enlarge and coalesce to
infect a larger part of the leaf.

40.  The galls are formed at the base of plants on
primary roots that took discoloured, scurfy and
hypertrophied with reduced development of
secondary roots.
 Such plants are less vigorous and subject to
lodging.
 (NIPHM – Hyderabad)

42.  Obligate parasite
 Produces intercellular mycelium with globular
haustoria and sporangia that arise through the
stomata.
 Sporangia are thin and branched monopodially
to form zoosporangia at the ends of the
branches.
 The zoosporangia break up, release biflagellate
zoospores
(Zimmer & Hoes, 1978).

43.  The pathogen survives through oospores in this
residue of the preceding sunflower crop in soil.
 Seed borne infection also occurs.
 After the winter, the oospores germinate,
especially in moist conditions of spring.
 Some oospores, however, remain dormant for
up to 14 year (Zimmer & Hoes, 1978).

44.  Cool weather with 16-18 temperature, cloudy
weather with winds and drizzle or High RH
favours infection and disease development.
 The disease is favored by high rainfall
conditions (relative humidity higher than 95%)
and temperature between 15ºC to 18ºC
(Davet et al., 1991).

45.  Combinations including metalaxyl or oxadixyl
gave good control of P. halstedii.
 Fungicides gave total protection, without
phytotoxicity, at 2.5 g commercial product/kg
seed for 10% metalaxyl + 48% mancozeb, and
at 3 g/kg seed for the combinations 10%
oxadixyl + 56% propineb and 8% oxadixyl +
56% mancozeb + 3.2% cymoxanil
(Achbani et al., 1999).

46.  Treatment of sunflower seeds with 1×108cfu/ml
of PGPR strain INR7 - decreased disease
severity and offered 51 and 54% protection
under green house and field conditions.
 Treatment of sunflower seeds with 5% chitosan -
decreased disease severity an offered 46 and
52% protection under greenhouse and field
conditions.
(Nandeesh Kumar et al., 2008).

47.  Trifloxystrobin as a foliar spray shows the
effective against the disease. (Sudisha et al.,
2010).
 Crop rotation of three years with ground
nut/castor/sorghum/maize; grow Resistant
variety hybrids like DRSH-1 and seed treatment
with Metalayxl 35SD @ 6g/kg seed.
(ICAR-IIOR – Hyderabad)

48. High yielding hybrids such as
BSH-1, KBSH-1, ICI-302, PKVSH- 27, DSH-1,
NSH-22, ITC-601, MSFH-17, SPIC-105,
Jwalamukhi, NARF- 114 and PKVSF-9,
Sidheswar are resistant to downy mildew.

49.  Important yield limiting disease in Great plains of
US
 Severity and incidence increased from 2002 &
2011
 More severe in the rabi season and causes a
considerable yield reduction whenever it
appears in early stages of crop growth.
 Under severe rust conditions, the seed yield
loss of 11-33% has been reported.

50.  Small round powdery pustules, with 1 to 2 mm
diameter, pale orange to black, distributed
randomly over the entire surface of the plant
 Common in lower leaves than to the top.
 Pustules- small yellow halos.
 At high levels of infection, stem, petiole and
floral parts may exhibit symptoms.
 The coalescence of pustules entire leaf surface-
premature leaf senescence, which causes
reduced yield & low seed quality.
 ( Pereyra & Escande, 1994)

52.  Autocieous and macrocyclic rust
 5 spore stages during its life cycle, four of which
are visible with the unaided eye.
 The earliest visible stage is the pycnial stage,
which has been observed as early as the first
week of June
 Stage is not seen often, but it occurs as a small
(1/4 inch or less) yellow-orange spot on the top
side of cotyledons or lower leaves

53.  Aecia -the underside of the leaf, immediately
opposite the pycnia.
 Aecia appear in clusters of orange cups similar
in size to the pycnia
 Uredinia pustules are small (1/16 inch) and can
occur on upper or undersides of leaves
(Pustules are filled with cinnamon-brown spores
(urediniospores) that may by surrounded by a
chlorotic halo and can be rubbed off easily.

54.  Uredinia pustules are small (1/16 inch) and can
occur on upper or undersides of leaves
(Pustules are filled with cinnamon-brown spores
(urediniospores) that may by surrounded by a
chlorotic halo and can be rubbed off easily.
 At season’s end, the uredinia are converted to
telia a black structure that does not rub off.

55. pycnial stage
Uredinial stage Telial stage

56.  Inoculum - overwintered as telia on sunflower
residue (previous crop residue or wild
sunflowers)
 Aecia produce aeciospores (disseminated by
wind) that infect the sunflower
 The disease spreads by wind-borne
uredospores from infected crop.

57.  Pathogen is favored by temperatures of 18ºC to
22ºC , under these conditions, can cause
epidemics
 86-92% relative humidity favoures high rust
intensity
(Pereyra & Escande, 1994).

58.  Removal and burning of infected crop residues
minimizes initial inoculum.
 Deep ploughing
 Crop rotation with non-host crops for 3 years
reduces the inoculum load in the soil
 Avoid high nitrogen rates and high plant
populations.
 Spraying of mancozeb or zineb at 0.25% two to
three times at 10 days interval is very effective in
control of the disease

59.  Application of sulphur fungicides, sulphur dust
(15 kg/ ha) or wettable sulphur 0.2% or mixture
of sulphur + zineb also gives good control of the
disease.
 Spraying of oxycarboxin 20 EC and benodanil
50WP at 0.4% two times at 30 days interval also
effectively control the disease.
 Application of boron to soil reduces the rust
incidence.

60.  DL-3-amino-n- butanoic acid (DL-b-
aminobutyric acid [BABA]) was the most
effective & sodium salicylate (NaSA) was the
least effective in protecting against rust
 BABA did not affect urediospores germination,
germ tube growth, appresorial formation or initial
ingress of P. helianthi, but strongly suppressed
mycelial colonization in the mesophyll and
consequently pustule and urediospore
formation. Amzalek and Cohen (2007)

61.  FRAC 3 products (Tebuconazole) and FRAC 11
products (Pyraclostrobin and Azoxystrobin), will
reduce rust.
(USDA 2011)

62.  First reported from Sri Lanka in 1927
 The fungus is reported to be soil, seed and
stubble borne
 The disease is more prevalent and economically
important in regions with hot, dry growing
seasons.
 It can cause 30-46% reduction in seed weight.
 The disease also causes lodging that incurs
indirect loss.

63.  Epidermis is removed, minute black
microsclerotia may be as to give a greyish black
look to the tissue
(Hoes, 1985; Kolte, 1985)

64.  Progressive wilting, premature dying, loss of
vigor, and reduced yield
 Responsible for seedling blight, damping off,
root rot, basal stem rot and early maturing of
sunflower crop
 After flowering are grey black discoloration and
shredding of plant tissue at the stem and top of
the taproot with getting hollowing of the stem

66.  Root inhibiting fungus and produces tuber or
cushion shaped 1-8 mm diameter black
sclerotia.
 The fungus is reported to be soil, seed and
stubble borne.
 Pycnidial stage: Macrophomina phaseolina
 Sclerotial stage : Rhizoctonia bataticola
 Affects the fibrovascular system of the roots and
basal internodes, impends the transport of
nutrients and water to the upper parts of the
plant. (Sinclair, 1982)

67.  Sclerotia serve as a primary means of survival
 The sclerotia float freely on soil surface when field
is flooded for irrigation and become primary
inoculum for emerging seedlings.
 Survive for more than 10 months under dry soil
conditions.
 Severity of the disease is directly related to the
population of viable sclerotia in the soil
(Kaisar, et al., 1988)

68.  Plants at seed development stage are stressed
and most vulnerable to infection.
 The disease is favoured by higher salt
concentration in irrigation water, higher
temperature (25-35°C) and moisture stress.

69.  Removal and destruction of diseased plants
 Deep summer ploughing
 Early season planting or choosing an early
maturing variety
 High incidence of the disease may be due to high
nitrogen and low phosphorus and potassium
 Seed treatment with thiram 3-4 g/kg seed reduces
the seed borne inoculum.

70.  Nitrogen applied as ammonium sulphate or
calcium nitrate and phosphorus as single super
phosphate is reported to be effective in
decreasing the incidence of the disease
 Plant crude extracts of
Occimum,E.globules(15%) were effective
against charcoal rot
 BCA- Bacillus strains, T.harzianum are also
found to be effective
 Fungicide Rizolex-3g/L
(Elaigwu et al.,2017)

71.  In India SND - Bagepally region of Kolar district
and around Bangalore in Karnataka during
1997.
 Later reported in Andhra Pradesh, Karnataka,
Tamil Nadu and Maharashtra.
 The intensity of disease ranges from 2 to 100%.
 The disease greatly reduces the growth and
seed yield.

72.  Field symptoms of the disease include mosaic
on leaves that leads to extensive necrosis of leaf
lamina, petiole, stem, floral calyx and complete
death of seedlings eventually
 Causes severe stunting with malformed head
filled with chaffy seeds
 Necrosis at bud formation stage makes the
capitulum to bend and twist resulting into
complete failure of seed setting and maturation.

74.  SND Causative Tobacco streak virus (TSV) was
first described by Johnson et al.,
 Species of the genus Ilarvirus, of the family
Bromoviridae
 Viruses having tripartite quasi isometric particles
of size 27 to 35 nm

75.  Weeds such as Trianthema portulacastrum,
Priva leptostachya, Digeria arvensis, Clitoria
ternata, Solanum nigrum, Vernonia cineraria,
Trichodesma indicum and some other species
were found to serve as hosts for sunflower
necrosis virus
 Virus spreads through transmission by thrips
Frankliniella schultzii.
 The main source of inoculum - pollen grains of
infected crop plants or weeds.
(Lavanya et al.,)

76.  Single thrip was enough to acquire and transmit
the virus from an infected to healthy sunflower
plant
 Acquisition Access Period (AAP) of 3 days
 Inoculation Access Period (IAP) of 6 days was
necessary for successful transmission of the
virus
(Pankaja et al.,2007)

77.  Sowing 7-11 rows of fast growing cereals (pearl
millet, sorghum or maize) as border crop around
fields which obstruct the movement of thrips from
landing on crop plants were found to reduce
disease incidence in sunflower
 Intercropping with red gram or castor was found to
reduce disease intensity

78.  Seed treatment either with imidacloprid at 5g/ kg
seed or thiomethoxam at 4g/ kg seed followed
by two sprays at 30 and 45 days found to
reduce necrosis disease. (IIOR-Hyderabad)
 Anti viral compounds:
Use of various anti viral materials such as
Prosopis, goatmilk and Bougainvillea in
combinations were used to induce the
resistance in sunflower against TSV-SF

80.  Important non edible oilseed crop of arid and
semi arid regions
 Ricinus communis – Euphorbiaceae
 In india- Gujarat, AP,Orissa,Tamil Nadu
 The seeds contain between 40% and 60% oil
that is rich in triglyceride, mainly ricinolein.
 The seed contains ricin, a toxin, which is also
present in lower concentrations throughout the
plant.

81.  SEEDLING BLIGHT- Phytophthora parasitica
 LEAF SPOT-Cercospora ricinella
 ALTERNARIA BLIGHT - Alternaria ricini
 POWDERY MILDEW- Leveillula taurica
 RUST- Melampsora ricini
 WILT- Fusarium oxysporum fsp. ricini

82.  First reported pusa Bihar -1909
 Occurs – Rainy season
 Severe in low lying areas & badly irrigated
regions
 Destroys the seedlings about 30 – 40%
 Hyderabad – 1947 Uttra pradesh- 1948

83.  Seedling death
 First makes its appearance on both the surfaces
of the cotyledonary leaves
 Form of roundish patch of dull green colour
which soon spreads to the point of attachment
causing the leaf to rot and hang down.

85.  The pathogen produces non-septate and hyaline
mycelium
 Inter and intra cellular mycelium
 Single colourless ovoid sporangium borne at the
tip
 Sporangia – zoospores
 Forms two germ tubes
 The fungus also produces oospores and
chlamydospores in adverse seasons.

86.  The pathogen survives in soil or collateral or
alternative hosts.
 Survive as soil borne oospores.
 Fungus also survives on other hosts like potato,
tomato, brinjal, sesamum etc.
 The secondary spread takes place through wind
borne sporangia.

87.  Continuous rainy weather.
 Low temperature (20-25°C).
 Low lying and ill drained soils.

88.  Seed dressing with T.viride or Metalaxyl @4g /kg
of seed
 Soil drenching with COC 3g/ L
 Avoid ill drained, damp and low lying place for
raising castor
 Growing resistant varieties
DCS-9, Jwala (48-1), Harita, GCH-4, GCH-5,
DCH-177, and GCH-7
( IIOR – Hyderabad)

89.  All the aerial parts of the plant, i.e., stem, leaves,
inflorescence and capsules are liable to be
attacked.
 Portion of the leaf and are irregular, scattered,
and have concentric rings.
 These are brown and later become covered
with bluish-green or sooty growth.
 Severe- spots coalesce and form big patches
resulting in premature defoliation of the plant
which gradually wilts away

91.  The pathogen produces erect or slightly curved,
light grey to brown conidiophores, which are
occasionally in groups.
 Conidia are produced in long chains. Conidia
are obclavate, light olive in colour with 5-16 cells
having transverse and longitudinal septa with a
beak at the tip.

92.  Seed borne both internally as well as externally
 Causes pre & post emergence D.off and foliage
blight
 Survives on hosts like J.pandurifolia & Bridelia
hamiltoniana
 Primary infection- seed
 Secondary infection – air borne conidia
(Pawar & Patel 1957)

93.  High RH 85 -90
 Low Temp 16 – 20 degree celcius
MANAGEMENT
 Removal of weed host
 Foliar application of 0.2 % @ 15 days interval
control the disease
 Proper dose of Nitrogen fertilizer

94.  Appears as minute brown specks surrounded by
a pale green halo.
 The spots enlarge to greyish white centre
portion with deep brown margin. The spots may
be 2-4 mm in diameter and when several spots
coalesce, large brown patches appear but
restricted by veins.
 Infected tissues often drop off leaving shot-hole
symptoms.
 In severe infections, the older leaves may be
blighted and withered

96.  The pathogen hyphae collect beneath the
epidermis and form a hymenial layer.
 Clusters of conidiophores emerge through
stomata or epidermis.
 They are septate and un branched with deep
brown base and light brown tip.
 The conidia are elongated, colourless, straight
or slightly curved, truncate at the base and
narrow at the tip with 2-7 septa.

97.  The pathogen remains as dormant mycelium in
the plant debris.
 The disease mainly spreads through wind borne
conidia.
MANAGEMENT
 Spraying twice with mancozeb 0.25% &
Carbendazim 500 g @ 10-15 days interval
 Seed treatment with captan or Thiram 2g/kg of
seed

98.  Prevalent during November to March at
Coimbatore in India
SYMPTOMS
 Typical mildew growth which is generally
confined to the under-surface of the leaf.
 When the infection is severe the upper-surface
is also covered by the whitish growth of the
fungus

100.  Endophytic
 Intercellular hyphae
 Condia hyaline borne at tip
 Sexual fruiting body chasmothecium
 Produces spongy cell Haustoria
SURVIVAL & SPREAD
 Survive on infected plant debris
 Secondary infection through air borne conidia

101.  Wettable Sulphur 2g/lit at 15 days interval,
starting from 3 months after sowing
 Spray 1ml hexaconazole or 2ml dinocap / litre
of water at fortnight intervals.
 The variety Jwala is resistant to this disease.

102.  Minute, orange-yellow coloured, raised pustules
appear with powdery masses on the lower
surface of the leaves and the corresponding
areas on the upper surface of the leaves are
yellow.
 Often the pustules are grouped in concentric
rings and coalesce together to for drying of
leaves.

104.  The pathogen produces only uredosori in castor
plants and other stages of the life cycle are
unknown.
 Uredospores are two kinds, one is thick walled
and other is thin walled.
 They are elliptical to round, orange-yellow
coloured and finely warty.
Survival & spread
 Survive in self sown crops
 Spreads through airborne uredospores.

105.  Rogue out the self-sown castor crops and other
weed hosts.
 Spray Mancozeb at 2kg/ha or Propioconazole
1l/ha.

106.  Necrosis of leaves starts from margins
spreading to interveinal areas and finally to the
whole leaf.
 Spilt open stem shows brownish discolouration
and white cottony growth of mycelia much
prominently in the pith of the stem

107.  Leaves droop and drop off leaving behind only
top leaves.
 Diseased plants are sickly in appearance.
 Wilting of plants, root degeneration, collar rot,
drooping of leaves and necrosis of affected
tissue and finally leading to death of plants.

109.  The fungus is soil-borne and remains in the soil
as saprophyte for 2-3 years.
 The disease is primarily transmitted through
infected seed pieces.
 The secondary spread is aided by wind, rain
and irrigation water.
EPIDEMIOLOGY
 High day temperature (30-35˚C).
 Low humidity (50-60%).
 Low soil moisture and alkaline soils

110.  Selection of disease free seeds.
 Grow tolerant and resistant varieties like Jyothi,
Jwala, GCH-4 DCH-30 and SHB 145.
 Avoid water logging
 Burning of crop debris
 Green manuring and intercropping with red
gram
 Treat the seeds with thiram @ 2g/ kg or
carbendiazim @ 2g/ kg seed.

111.  Seed treatment with 4g of Trichoderma viride
talc formulation.
 Multiplication of 2kg of T.viride formulation by
mixing in 50kg farm yard manure
 Sprinkling water and covering with polythene
sheet for 15days and then applying between
rows of the crops is helpful in reducing the
incidence.

112.  Seed treatment with captan/Thiram @3 kg or
Carbendazim 2g/kg seed or T. viride 10g/kg for
control of seed borne diseases
 Soil application of T. viride (2.5 kg mixed with
125kg FYM /ha)
 Resistant varieties-
Jwala,Haritha,DCS107,GCH-7,GCH-4,DCH-
177,519- Tolerate wilt
 Crop rotation with milets and inter cropping with
Red gram 1:1 ratio.