Transcript Viral Diseases in Banana

Viral Diseases in Banana
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Major Viral Diseases in Banana
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Kootaivazhai in Poovan
Bract Mosaic
Bunchy Top
Streak
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Kootaivazhai Symptoms in poovan
In Tamil Nadu, the banana cv. Poovan
is characterized by conical and ill filled
fruits
with
prominent
central
core
having many under developed non
viable seed structure rendering the
fruits inedible.
Reasons
Insufficient growth hormones (Auxin) for
the redevelopment of fruit and hence the
fruits are forced to produced seeds .
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Management practices
This disorder can be overcome by spaying 2, 4D 20 ppm when the last hand of bunch is
opened.
The same chemical at same dose
stage result in increased bunch weight
and uniform grade especially in cvs.
Nendran and monthan.
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Bract Mosaic Virus
Banana bract mosic virus (BBrMV,) -
locally known as kokkan.
Symptom
develops
in
primarily
transmitted through infected suckers.
Transmission
Primary: Infected Sucker
Secondary: mealy bugs
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Symptoms
Yellow streaks on leaves. Splitting of the
pseudo stem.
Abnormal emergence of the bunch from
the middle of the pseudo stem.
Produce fewer fruits of smaller size.
Dark reddish-brown mosaic symptoms,
which are especially obvious in bracts.
Spindle-shaped chlorotic streaks running
parallel to the veins.
Distinctive dark colored mosaic patterns, stripes or
spindle-shaped streaks are visible.
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Green or reddish-brown(depending on cultivar) streaks or
spindle shaped lesions on the petioles and a tendency towards
a congested leaf arrangement.
Management Practices:
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Transmission by mealy bugs.
Requires early detection, and immediate eradication of infected
plants.
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Effective control of the disease, similar to that of other viral
diseases.
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virus-free propagating materials should be planted.
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Bunchy Top
Symptoms
The presence of dark-green spots on
the petioles, midribs, and leaf veins of
the newly emerging leaves.
The
infected
leaves
are
erect,
narrow, stunted, and often have
yellow leaf margins.
The leaves become smaller as the
disease progresses.
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Eventually, the crown of the plant
is composed of only stunted
leaves,
producing
a
"bunchy
top", hence the name.
The infected plant does not
produce any fruit or the
bunch does not emerge from
the pseudo stem.
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Mode of Spread
 Banana aphids (Pentalonia nigronevosa)
 Infected planting materials
 Volunteer plants that serve as alternate hosts like
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Bird of paradise,
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Ginger, and
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Wild ban
 Weeds
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Management Practices
 Using diseased-free planting materials controlling
of aphids,
using soapy water or insecticidal soap.
 Spray the Plants thoroughly, importantly on petioles, furled leaves,
whorls, or on young sucker removing and rouging of infected
banana plants. Chop, dry, and bury the infected plants.
 Control
vector
by
spraying
methyl
demoton
1
ml/l.
or
Monocrotophos, 2 ml/l. or Phosphomidon 1 ml / lit. or Injection of
Monocrotophos 1 ml / plant (1 ml diluted in 4 ml). Infected plants
are destroyed using 4ml of 2, 4, D (50g in 400 ml of water).
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Banana Streak Virus
Banana streak virus (BSV) is an important disease of Musa and
affecting the productivity of both bananas and plantains.
Reported in nearly all countries where this crop is grown
including Mauritius, India and many countries of the African
continent.
Symptoms
Disease severity is very variable, and
probably depends on environmental
conditions, as well as on host and virus
(Cont)..
genotypes.
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The most characteristic foliar
symptoms
of
infection
chlorotic
streaks,
are
which
become necrotic with time.
The leaf lamina may also be
narrower, thicker and become
torn.
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Stunting of the plant, constriction of the bunch on emergence
(choking), altered phyllotaxis (leaves arranged in a single
vertical plane instead of the normal spiral pattern), and
detachment and splitting of the outer leaf sheaths of the pseudo
stem.
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Management Practices
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The eradication of infected plants.
The use of BSV-free planting materials.
BSV can be carried in in-vitro plantlets, as it is not
eliminated by shoot-tip culture.
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Virus particles can only be detected in areas of leaf tissue
with symptoms.
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Parts of leaves with pronounced symptoms should be
used for serological indexing.
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To sum up:
Viral diseases are mostly transmitted through vectors. It affect the
quality and vigour of the plant.
 Kottavazhai in banana – ill filled development of fruits with
unviable seedy structure it can be overcome by application of 2,
4 – D 20ppm at the last hand of bunch opened.
 Banana bract mosaic – This disease transmitted through
aphids it caused symptom of dark reddish brown mosaic it may
be avoided using free propagating materials.
 Bunchy top – Stunted growth of plant with bunchy appearance.
This disease transmitted through aphids. The disease controlled
application of monocrotophos 2 ml/ lit.
 Banana streak virus - Chlorotic spots on leaf lamina. Use virus
free planting material.
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