Transcript winter flower

Introduction
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Cotton comes from the family Malvaceae. Two
species of cotton are grown in India : desi cotton
Gossypium arborium and American cotton,
Gossypium hirsutum. The desi cotton is less
infested by pests. Over 1326 species of insect pests
attack cotton crop in the world. Only 162 species
infest cotton in India. Of these only 15 are major
pests. Among these are
Pink Bollworm (Pectinophora gossypiella)
Spotted Bollworm (Earias insulana)
Cotton Leaf Roller (Sylepta derogata)
Red Cotton Bug (Dysdercus koenigii)
Cotton Grey weevil (myllocerus undecimpustulatus)
Pectinophora gossypiella – The Pink Bollworm
Phylum – Arthropoda
Class – Insecta
Order – Lepidoptera
Family – Gelechiidae
Genus – Pectinophora
Species - gossypiella
Distribution. - The pink bollworm occurs all over
India in
cotton growing regions.
Food Plants. - Besides cotton, pink bollworm also
feeds on
lady’s finger, hollyhock and other malvaceous plants.
• Eggs are laid on the young green cotton bolls, sometimes
on flower buds, new shoots, leaves & in leaf axils.
• They are white, flat & oval.
The Caterpillar or The Larva
• The Larval life lasts for 2 weeks & almost entirely passed in
the seeds.
• Larva grows 8-10 mm. when it has pink body, brown head.
• Winter is passed in the larval stage & not in pupal stage.
• The larva leaves the boll & pupates in a silk cocoon in the soil
or under fallen leaves.
• The Moth emerges after 7 days. Its about 8mm. Long deep brown
insect with black & white spots on the forewings , & deeply fringed
margin of the hindwings.
• It is nocturnal as other moths.
• Mating occurs very next night after emergence of the adults.
• Female lays eggs on the second to fourth night & dies.
• There may be 4-6 generations in a year. ( May to November )
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The Caterpillars destroy the seeds & check lint
formation.
They also damage the already formed ‘Kapas’. The
attacked bolls falls off prematurely.
Moreover the bolls are exposed to attacks of
bacteria & fungi.
The Pink Bollworm may Cause about 10-30% loss
of Cotton yield.
The Damaged crop gives less seeds, less oil &
inferior fibre.
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The fallen leaves, buds & bolls should be collected
& destroyed.
Ploughing the field deep in February end &
exposing the hibernating larvae may kill the latter.
The off-season cotton sprouts & alternate host
plants should be destroyed.
Resistant varieties of cotton should be grown.
Spray of Endosulfan or Carbaryl is an effective
control of pink bollworm.
Seeds should be exposed in a thin layer to
May/June Sun for 3-4 hours to kill hibernating
larvae before sowing.
Systematic
Position
Phylum – Arthropoda
Class – Insecta
Order – Hemiptera
Family – Pyrrhocoridae
Genus – Dysdercus
Species - koenigii
Distribution – The red cotton bug occurs all over India almost
throughout the year.
It is a minor pest of cotton in Punjab & UP.
Food Plants – The Red Cotton Bug also attacks Sweet potato,
Tobacco, Lady’s finger, Hollyhock & other Malvaceous plants
with oily seeds.
• The female lays about
100-130 rounded, yellow
eggs in groups in the
moist soil or in the
ground crevices.
• The eggs hatch in 7-8
days in tiny nymphs with
flabby abdomen.
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The nymphs hatches in 7-8 days from eggs.
The nymphs become adults in about 40-80 days
after 5 moults.
During growth, they become more slender &
acquire black markings on the body.
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The adult bug has an elongated, slender, bright red
body with distinct white bands across the
abdomen.
The female is 15mm. Long & the male is 13mm.
long.
Both have a triangular head with long triangular
head with long, 4-jointed black antennae,
prominent eyes & piercing-sucking mouth parts,
forming a sharp-pointed proboscis.
The forewings, called hemelytra, are thick & horny
in the anterior half and membranous & black in the
posterior half.
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They crossed each other at rest, forming a
diamond shaped, black area on the back.
Each Hemelytron has a black spot near the middle.
The hind wings are membranous.
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The adults as well as nymphs sucks sap from
the seeds of green or ripe cotton bolls.
This causes poor lint formation & shrivelling of
the bolls & destroys the germinating power of
the seeds.
They also inject into the bolls a micro-organism
that causes red stains on the cotton fibres.
The bug therefore called as red cotton stainer.
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The bugs may be hand picked & killed.
Infested plants may be shaken over a pan
containing water with a film of kerosene oil.
This will trap & kill the bugs.
Moistened cotton seeds may be hung up at
places to attract the bugs. From here, they can
be shaken over a pan containing water with a
film of kerosene oil.
Myllocerus undecimpustulatus-Cotton Grey weevil
Systematic
Position
Phylum – Arthropoda
Class – Insecta
Order – Coleoptera
Family – Curculionidae
Genus – Myllocerus
Species - undecimpustulatus
Distribution – The Cotton Grey Weevil is widely
distributed in India.
It’s a minor pest of cotton.
Food Plants – The Cotton Grey Weevil also attacks
Sweet potato, Tobacco, Lady’s finger, Hollyhock &
other Malvaceous plants with oily seeds.
• The female Weevil
ovoid, light yellow
eggs in the soil.
• The eggs hatch in
3-5 days.
• The emerging young
grubs are white, legless,
cylindrical creatures.
• Feed on the roots of
cotton plants & become
full-grown, about 8mm
long in 1-2 months.
• Then they pupate in the soil
within earthen cells, forming
creamy white pupae.
• The white pupae turn into
the adults in about one week.
• The Adult beetles are grey.
• They are about 3-6mm.
Long.
• They have snout-like head &
strong pincer-like jaws.
•They feed on aerial parts of the
host plant.
•They live for 8 to 11 days in
summers & 4-5 months in winter.
•The entire life history takes about
6-8 weeks.
•There are 3-4 generations in a year.
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Both grubs & adults damage cotton crops. The
Adults feeds on leaves, flower buds, flowers &
young bolls.
The Grubs feeds on roots. There may be 5-30% loss
of the yield.
They also feeds on a variety of other crops & fruit
trees.
Control (Management)
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Ploughing the soil about 7-8cm. Deep will
expose & kill the eggs, grubs & pupae.
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A Spray of Carbaryl is effective against the
cotton grey weevils.