various diseases of banana

2. SHRAMSHAKTI COLLEGE OF
AGRICULTURE,
MALDAD, TAL- SANGAMNER, DIST-
AHMEDNAGAR
Course No: PATH-354
Course Title: Diseases of Field & Horticultural Crops
& their Management
Credits: 2+1=3
Name of Topic: Diseases of Banana

3. DISEASES OF BANANA
1. Panama wilt
2. Bacterial wilt,
3. Sigatoka
4. Bunchy top

4. Panama Wilt: Fusarium oxysporum f.sp cubense
Symptom:
Externally, the first obvious signs of disease in most
varieties are wilting and a light yellow colouring of the
lower leaves, most prominent around the margins. They
eventually turn a bright yellow colour with dead
leaf margins.
Splitting of pseudostem base is a characteristic symptom.
When a cross-section is cut, the discolouration appears in
a circular pattern around the centre of the rhizome where
the infection concentrates due to the arrangement of the
vessels.
As symptoms progress into the pseudo-stem, continuous
lines of discolouration are evident when the plant is cut
longitudinally
The disease is soil borne and the fungus enters the roots
through the fine laterals.
The pathogen is easily spread by infected rhizomes or
suckers, farm implements or vehicles, irrigation water

5. Favourable conditions:
 Saturated poorly drained heavy soils.
 Cultivation of susceptible cultivars like
Amritapani.
Infection by burrowing nematode,
Radopholus similis, predisposes the plants to
disease

6. Disease Cycle:
Primary: Chlamydospores in soil and
propagules in infected suckers
used for planting.
Secondary: Micro and macro conidia through
irrigation water

7. MANAGEMENT:
 Proper care should be given when planting susceptible
cultivators such Rasthali, Monthan, Karpuravalli, Kadali,
Pachanandan by selecting healthy suckers from disease
fields.
 Remove and destroy infested plant material after harvest.
 Paring (removal of roots and outer skin of corm) and
dipping of the suckers in clay slurry and sprinkled with
Carbofuran granules at 40g/corm.
 Soil drenching of Carbendazim 0.1 per cent solution
around the pseudostem at bimonthly intervals starting
from five months after planting
 Corm injection of 3 ml of 2% Carbendezim injected in the
corm by making a hole to a depth of 10cm with 45 degree
angle on 5 and 7 th month.

8. Bacterial wilt (moko): Pseudomonas solanacearum
/ Burkholderia solanacearum
Symptoms:
Leaves become yellow and progress upwards.
The petiole breaks and leaves hang.
When it is cut open discolouration in vascular
region with pale yellow to dark brown colour.
The discolouration is in the central portion of the
corm.
Internal rot of fruits with dark brown discoloration.
When the pseudostem is cut transversely bacterial
ooze can be seen.

10. Favourable conditions
Crop residues infected with pathogen in
the field.
Injured roots caused by farm tools or by
soil pests .
Warm temperature and high soil moisture.
Slightly acidic soils .
Poor and unfertile soils .
Infestation by nematodes

11. Pathogen :
It is rod shaped, gram negative
bacterium with one polar flagellum.
Mode of spread and survival:
The pathogen is soil borne, it survives in
susceptible hosts like banana and Heliconia
spp. Secondary spread with irrigation water
or through rain splash.

12. Management :
 Grow relatively resistant varieties like poovan and
monthan
 Adopt strict plant quarantine and phytosanitary
measures and plant healthy suckers
 Eradicate infected plant. Expose soil to direct sunlight.
 Eradicate infected plants and suckers by rouging or
killing in situ by application of herbicides
 Exposure of soil to sunlight during dry hot weather
 Application Pseudomonas fluorescens @
2.5kg/ha bactericide can also be applied along with
farmyard manure and neem cake. About 60 mg
of Pseudomonas fluorescens (in a capsule) can be applied
in a 10 cm deep hole made in the corm (corm
injection).

13. Fallowing and crop rotation is advisable.
Crop rotation (3 years rotation with sugarcane
or rice) & providing good drainage
Disinfection of pruning tools.
Disinfestations of tools with formaldehyde
diluted with water in 1:3 ratio
Providing good drainage.

14. Economic impact
 Yellow Sigatoka: Worldwide in distribution.
 First observed in Java in 1902
 Epidemic in 1913 in Sigatoka valley in Fiji.
 In India, yellow sigatoka is a serious threat to
banana production in the states of Assam, T.N,
Karnataka and A.P..
 Black sigatoka is not prevalent in India
Yellow Sigatoka – Mycosphaerella musicola
(I.S: Pseudocercospora musae)
Black sigatoka or black leaf streak – M. fijiensis
(I.S: Paracercospora fijiensis)

15. Symptoms:
 On leaves small light yellow or brownish green
narrow streaks appear.
 They enlarge in size becomes linear, oblong, brown
to black spots with dark brown brand and yellow
halo.
 Black specks of fungal fruitification appear in the
affected leaves.
 Rapid drying and defoliation of the leaves.
 Early symptoms appear on the lower leaves.
 Initially small reddish brown specks develop on
leaves near the tip or margin of lamina.

16.  Specks may also be produced near the midrib.
 Specks increase in size and turn in to spindle
shaped spots with reddish brown margin and gray
centre surrounded by a yellow halo.
 Spots formed near the midrib enlarge and extend
towards the margin of lamina.
 Spots coalesce and the entire spotted area appears
dried.
 Disease gradually progresses on to upper leaves.
 Infection becomes severe after bunch emergence
with the entire foliage infected under favourable
conditions.
 Fruits in bunches of infected plants are under
developed and may ripen prematurely

18. Favourable conditions:
High humidity, heavy dew and rainy
weather with temp above 21 degree.
Prolonged leaf wetness periods.
Poor drainage and low soil fertility
particularly of potassium.
Closer planting.
Susceptible cultivars like Grand Naine,
Dwarf Cavendish and Giant Cavendish.
More suckers in a mat because of non
removal

19. Management :-
Planting banana in well drained soils
Growing moderately resistant cultivars like
Karpura Chakkerakeli
Planting at recommended density (1000
plants/acre)
Pruning suckers periodically to avoid
overcrowding in the field
Removal and destruction of affected leaves
followed by spraying with BM 1% + linseed oil
2%

20. Applying recommended dose of potassium
fertilizer.
Spraying mancozeb or cholorothalonil @ 0.2%
suspended in mineral (paraffin) oil.
Spraying chlorothalonil 0.2% with non ionic
adhesive in pre-monsoon period and
propiconazole 0.1% interspersed with
tridemorph 0.1% at 20 days interval in rainy
period.

21. Banana bunchy top: Banana bunchy top virus
Economic Importance
 The disease is covered by domestic quarantine
regulations. Losses were estimated to be Rs.4
crores every year and 100% loss occurs if infected
suckers are planted.
 Around 1940, introduced into India from
Srilanka through cyclone
 The virus is a domestic quarantine pest in India.
 The movement of planting suckers from North
East, Tamil Nadu, Karnataka and Kerala to other
parts of the country is restricted

22. Symptoms:
 Subsequent leaving show the same symptoms and
are dwarfed.
 Dark broken bands of green tissues on the veins,
leaves and petioles.
 Plants are extremely stunted.
 Leaves are reduced in size marginal chlorosis and
curling.
 Leaves upright and become brittle. Many leaves are
crowded at the top.
 Branches size will very small.
 If infected earlier no bunch will be produced.
 The disease is transmitted primarily by infected
suckers.

24. Favorable conditions :
Progressively increasing temperature from February
onwards favours virus spread and symptom
expression
Prevalence of infected reservoir host (Canna,
Heliconia, Strelitzia)
Prevalence of aphid vector
Spread:
Primary: Virus particles through diseased suckers used
for planting
Secondary: Virus particles transmitted by banana black
aphid( Pentalonia nigronervosa )
Colocasia esculenta serves as a latent reservoir host

25. Management :
 Adoption of strict quarantine measures
 Use of only certified banana suckers or tissue culture
plants for planting
 Periodical monitoring and rouging of infected plants
with all suckers in the mat by rouging or killing by
injecting herbicide, 2, 4-D.
 Raising barrier crops like sunhemp in three to four
rows on the field boundaries to check aphids from
entering the fields from neighbouring infected fields .
 Vector control with systemic insecticides, viz.,
Phosphomidon @ 1ml/l or Methyl demeton or Dimethoate @
2 ml/l .
 Discouraging intercropping with Colocasia in disease
endemic areas

26. Thank You