1. Introduction
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)
Cotton Whitefly (Bemisia tabaci)

2. Systematic Position Pectinophora gossypiella – The Pink Bollworm
Phylum – Arthropoda
Class – Insecta
Order – Lepidoptera
Family – Gelechiidae
Genus – Pectinophora
Species - gossypiella

3. Distribution
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.

4. Life History

5. Eggs of the Pink Bollworm
Eggs are laid on the young green cotton bolls, sometimes on flower buds, new shoots, leaves & in leaf axils.
They are white, flat & oval.

6. 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.

7. The Adult
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 )

8. Damage 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.

9. Control (Management)
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.

10. Dysdercus koenigii-The Red Cotton Bug
Systematic Position
Phylum – Arthropoda
Class – Insecta
Order – Hemiptera
Family – Pyrrhocoridae
Genus – Dysdercus
Species - koenigii

11. Distribution
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.

12. Eggs of the red cotton bug
The female lays about 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.

13. The Nymph The nymphs hatches in 7-8 days from eggs.
The nymphs become adults in about days after 5 moults.
During growth, they become more slender & acquire black markings on the body.

14. The Adult
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.

15. 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.

16. Damage
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.

17. Control (Management) 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.

18. Systematic Position Myllocerus undecimpustulatus-Cotton Grey weevil
Phylum – Arthropoda
Class – Insecta
Order – Coleoptera
Family – Curculionidae
Genus – Myllocerus
Species - undecimpustulatus

19. Distribution
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.

20. Life History

21. Eggs of the Cotton Grey Weevil
The female Weevil ovoid, light yellow eggs in the soil.
The eggs hatch in 3-5 days.

22. The Grub & The Pupa
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.

23. The Adult 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.

24. Damage Control (Management)
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)
Ploughing the soil about 7-8cm. Deep will expose & kill the eggs, grubs & pupae.
A Spray of Carbaryl is effective against the cotton grey weevils.