MD. RAMJAN CHF, CAU, Pasighat

1. Diseases of Cole crops

2. Damping off
(Rhizoctonia solani, Phytobhthora spp. Pythium spp.)
 It is very common fungal
disease of seedlings in nursery.
 The affected seedlings rot at
collar region and topple down
on the ground.
 The base of stem is brown,
constricted, dry and demarked
by deep brown and reddish
borders.
 High temperature, excessive
salt concentration, excessive
soil moisture or water logging
and poor soil aeration are the
main predisposing factors that
favor damping off disease.

3. Control measure
 Follow long crop rotation
with cereals.
 Sterilize the soil with 1%
formaline.
 Soak the seeds in tap water
for 30 minutes followed by
hot water dip at 52˚C.
 Provide good drainage.
 Maintain moderate soil
moisture in nursery.
 Always sow the seed
sparsely to avoid
overcrowding of seedlings.
 Drench the nursery beds
with 0.25% Ridomil MZ-
72 WP solution.

4. Black rot
(Xanthomonas campestris)
 It is seed borne disease by
which cauliflower is affected
both in nursery and in field.
 The plant may be affected at
any stage during its growth.
 Infected leaves show
yellowing at margins and the
necrosis towards the center of
the leaf, forming V-shaped
area .
 The veins become brown or
dark and vascular regions of
the main stem discolored.
 Leaves fall prematurely due to
formation of abscission layer.

5. Control measure
Follow long crop
rotation of at least 3-5
years.
Treat the seed with
hot water at 52˚C for
an hour.
Protective spray with
Indofil M-45 @
100ppm and repeat at
least 8-10 days
interval.
Small rotten area on
the curd may be cut
with knife and painted
with Bordeaux
mixture @ 4: 4: 50.

6. Sclerotinia rot
(Sclerotinia sclerotiorum)
 The first symptoms of
disease appears as wet soft
lesion on cauliflower curd,
and leaf scar on stump
region left behind due to
defoliation of older leaves.
 Later, these spots enlarge
into watery rotten mass of
tissues.
 The affected parts of seed
crops wilt and die later on.

7. Control measure
Follow crop rotation
with cereals.
Pick up and destroy
the diseased leaves.
Spray the crop with
carbendazim 0.05%
combine with
mancozeb 0.2%.

8. Downy mildew
Peronospora parasitica)
 The disease is prevalent in
cooler regions of the world.
 Small chlorotic, irregular,
translucent, light green
lesions usually delimited by
the veins appear on leaves
under cool and moist
conditions.
 The young leaves less
susceptible than older ones.
 Infection occurs more readily
on lower surface than on
upper ones.
 The infected curds exhibit
brownish to blackish look.

9. Control measure
Follow long crop
rotation with cereals.
Treat the seed with
Captan 2.5-3.0 g/kg
of seed.
Adopt the clean
cultivation.
Spray the crop with
Ridomil MZ-72 or
mancozeb at 0.25% at
10-15 days interval
starting from the first
appearance of
symptoms.

10. Alternaria leaf spot
(Alternaria brassicicola)
 The spots appears as small
dark colored areas, which
expand rapidly to form
circular lesion up to 1.0
cm dia.
 The enlargement of spots
may be in concentric
circles.
 In some conditions, the
cauliflower curd also
show browning ,
beginning at the margins
of flower clusters.

11. Control measure
Depending up on
infection, 2-4
sprays of Indofil
M-45, Difolatan at
0.2%, or Blitox @
0.5-0.75% at 15
days interval are
effective.

12. Bacterial soft rot
(Erwinia carotovora)
 The first symptoms
appear on fleshy
affected tissue as
small water soaked
lesions, which
enlarge rapidly.
 The affected plants
show a soft , slimy,
foul smelling rot
and fail to bolt.

13. Control measure
Spraying the
streptocycline or
plantomycine @ 500
ppm in combination
with copper
oxychloride 2000 ppm
at fortnightly interval
starting from
appearance of first
symptoms of disease.

14. Wire-stem
(Rhizoctonia solani)
 This is mostly appears in
cabbage, in warm and
humid areas and seriously
affects the crop at seedling
stage.
 The infested young
seedlings show soft and
water soaked spots on the
stem near collar region,
and as a result, the
seedling topple down.
 The lower part of the stem
often shows dark
discoloration over a length
of several centimeters.
 The portion hard and
thinner than the healthy
portion, hence, it is named
as wire-stem.

15. Control measure
 Follow integrated disease
management.
 Plough the field deep in hot
summer months.
 Use varieties resistant to wire-stem.
 Soak the seed in hot water of 52˚C
for half an hour.
 Use only healthy seedling for
transplanting.
 Plant the seedling shallow.
 Use compost and photodegradable
plastic mulch.
 Follow field and Phyto-sanitation.
 Provide proper drainage.
 Apply selective fungicides or
methyl bromide in nursery beds.

16. Yellow-wilt
(Fusarium oxysporum)
 Cabbage and cauliflower
highly susceptible to yellows
when grown in warm weather.
 The foliage of infected plants
turn yellow, dies and
eventually drops off.
 The symptoms appear first on
lower leaves.
 The disease may affect the
plants at any stage.
 young seedling show
damping off.
 Heavy infection causes death
of the plants but sudden
withering does not usually
occur.

17. Control measure
Follow long crop
rotation.
Sterilize the soil
with steam.
Dipping of roots in
1% zinc dimethyl
ditiocarbamate for
30 minutes before
transplanting.

18. Black leg
(Phoma lingam)
 It is appearing frequently in
cabbage growing areas of
Kullu Valley.
 On seedling, black pucnidia
are visible as small dots on the
hypocotyl and on the cotyledon
of young plant resulting into
their death.
 In advance stages stem shows
sunken grayish brown oval
spots, often with purple and
black margins.
 On leaves is causes sunken,
irregular grayish spots with a
purplish to black margin.

19. Control measure
Use clean seed as a
preventive measure.
Follow long crop
rotation.
Provide hot water
treatment at 50˚C for
30 minutes.
Treat the seed with
Benomyl slurry
combine with
Thiram.
Follow field and
phyto-sanitary.

20. Club root
(Plasmodiophora brassicae)
 Especially in temperate region.
 It affect the underground
portion but symptoms on
above ground portion are
apparent only in advance
stages.
 Formation of small or large
spindle like spherical, club
shaped swelling on roots and
rootlets.
 The hypertrophy of tissue
disrupts water supply , which
result in pale green to
yellowish foliage, flagging and
wilting of plants.
 Club roots is particular
prevalent on soils with a pH
below 7.

21. Control measure
 Raise the pH of acidic soil by
adding lime.
 Raise the crop in well-drained
soil with pH slightly above
neutral.
 Sterilize the nursery bed’s.
 Use fungicides like
carbendazim, Deconil,
Thiophanate methyl, Zineb,.
 The most practical control
measure is crop rotation.