Pests of cotton and it's management

1. LEC. 21. BIOECOLOGY AND MANAGEMENT OF
INSECT PESTS OF COTTON

2. Sucking pests on leaves
1. Leafhopper
2. Aphid
3. Thrips
4. Whitefly
5. Scales
6. Mealy bug
Sucking pests on bolls
7. Red cotton bug
8. Dusky cotton bug
Borers
1. Stem weevil
2. Shoot weevil
3. Spotted bollworm
4. American bollworm
5. Pink bollworm
6. Red bollworm
7. Surface weevil
8. Stem borer
Defoliators
1. Leaf roller
2. Semi loopers
3. Tobacco caterpillar
4. Ash weevil
Other pests
1. Flower weevil
2. Tobacco caterpillar
3. Hairy caterpillar
4. Cotton grasshopper

3. 1 Leafhopper Amrasca devastans Cicadellidae Hemiptera
2 Thrips Thrips tabaci Thripidae Thysanoptera
3 Whitefly Bemisia tabaci Aleyrodidae Hemiptera
4 Spotted
bollworms
Earias vittella Noctuidae Lepidoptera
5 Spiny bollworm E. insulana Noctuidae Lepidoptera
6 American
bollworm/
Green bollworm
Helicoverpa
armigera
Noctuidae Lepidoptera
7 Cotton pink
bollworm
Pectinophora
gossypiella
Gelechiidae Lepidoptera
8 Stem weevil Pempherulus affinis Curculionidae Coleoptera

4. SUCKING PESTS
Leafhopper / Jassid, Amrasca devastans
Cicadellidae; Hemiptera
• Introduced with American cotton
(G. hirsutum, G. barbadense)
• More damage on young seedlings
(80-100%)
• Host range
– Bhendi, hollyhock, brinjal, potato,
mesta, sunflower, cucurbits
• More activity -dry conditions in early
stages

5. SUCKING PESTS
Leafhopper / Jassid, Amrasca devastans
Cicadellidae; Hemiptera
Symptoms :
• Causes phyto-toxaemia
– Injection of saliva into plant tissues
• Yellowing of leaves
• Crinkling and backward curling of leaves
• Bronzing and hopper burn
• Complete drying and dropping of leaves
• Stunted growth
• Less number of flowers, bolls, less seed
weight and reduced quality of lint

6. • Adults
– Greenish / greenish yellow- wedge shaped - move in all directions on leaf
under surface
• Eggs
– Singly - within leaf veins in parenchyma cells between vascular bundles
and epidermis on leaf upper surface, mostly on matured leaves
(35-40 days)
• Nymphs
– Initially pale yellow - turning green slowly with sucking of sap.
• Life cycle
– EP : 4-11 d ; NP : 7-8 d (Summer) : 25 d (W) AP : 35-40 d (S) 50 – 60 d (W)
– Eleven generations in a year
BIONOMICS

7. • Resistant varies MCU 5, MCU 7, Anjali Chairy
• Avoid late sowing
• Seed treatment – Thiamethoxam 70 WS or
Imidacloprid 70 WS 7 g/kg
• Proper irrigation in young stages to overcome
drought
• Do not use high doses of N fertilizers
• Use yellow sticky traps
• Release predators Chrysoperla carnea or
Coccinella septumpunctata, Scymnus or Syrphus
• Conserve spiders Distina albida and ants like
Componotus sp.
• ETL : 50/50 leaves : (1-2 /leaf)
• Imidacloprid 200 SL 100 ml/Acetamiprid 20 SP 50
g/thiamethoxam 25 WG 100 g/ha
• Neem oil 3% or NSKE 5% - 3 times – fortnightly
• Azadirachtin 10,000 ppm @ 500 ml/ha
MANAGEMENT

8. Thrips Thrips tabaci, Scirtothrips dorsalis
(Thripidae : Thysanoptera)
• Hosts : Bhendi, Chillies, brinjal, onion,
tomato, sunflower, mango, citrus, tea
• Damage
– Nymphs and adults lacerate tissues,
desap
– Leaves shrivel with ragged edges, brittle,
fall off & malformed
– Silvery metallic appearance on leaf
under surface
• T. tabaci – on flower ; S. dorsalis – on leaves
– Minute, slender yellowish active nymphs
beneath veins on veinlets

9. Bionomics
• Adults
– small, yellowish or brown with fringed wings
• Nymphs
– minute, slender yellowish – 2 instars prepupa
• Reproduction – sexual and parthenogenetic
• Eggs -laid within plant tissues of tender leaves 40-
50 eggs / ♀
• Life cycle : EP : 2-3 d ; NP : 5-8 d ; PP : 3-5 d.
Management
• ETL 50 thrips /5 Leaves (10 thrips/leaf- All India
data)
– Neem oil, NSKE 5%
– Fish Oil Rosin Soap (FORS) 25-40 g/lit
– Fipronil 5% SC 1 litre/ha

10. Cotton whitefly, Bemisia tabaci
Aleyrodidae: Hemiptera
• Serious pest on cotton- synthetic pyrethroids -
indiscriminately used
• Highly polyphagous
– Tobacco, GG, BG, Cassava, bhendi, hollyhock, safflower,
sunflower, Achyranthus aspera
• Damage and Symptoms
– Green nymphs – in colonies on leaf under surface
desapping
– Leaves turn chlorotic, drop down
– Sooty mould
– Reduced vigour, boll-shedding, buds, flowers, improper
boll-bursting
– Small mosquito-like insects fly in clouds, immediately
settle on nearby objects
• Early morning activity seen easily
• VECTOR : Cotton leaf curl disease

11. • Adult
– Small, moth like with white hyaline wings dusted with
white powdery scales : body yellow
• Nymphs : Green on leaf undersurface
• Eggs
– Stalked singly on leaf under surface – 120 eggs / female
• Life cycle
– EP : 3-5 d (S) ; 30-3 d (W) NP : 9-15 d (S) ; 17-80 d (W)
PP : 2-8 d
• Parthenogenesis is common
• 10-12 generations / year
Bionomics

12. • ETL: 8-10 adults or 20 nymphs per plant
• Avoid late sowing
• Removal and destruction of alternate weed hosts like Abutilon
indicum (Thuthi), Solanum nigrum (Manathakali/ Milaguthakali,
Chukkittikeerai) and Hibiscus ficulensus from the fields and
neighbouring areas and maintaining field sanitation
• Adopting crop rotation with non-preferred hosts such as sorghum,
ragi, maize etc., for the whitefly to check the build up of the pest
• Cultivate alternate host crops such as tomato and castor on the
boundaries to trap and destroy them
• Tolerant varieties like Kanchana, Supriya, LK 861 with glabrous leaf
surface
• Timely sowing - Winter irrigation (August – September); Summer
(February – March); Short duration (January – February); Medium
(January – February)
• Wider spacing - 45 – 60 cm (rows) and 15-60 cm (plants)
MANAGEMENT

13. • Judicious application of fertilizers to arrest excess vegetable growth
• Monitoring using yellow pan sticky traps or sticky traps at 1 foot height
• Collection and disposal of infested plant samples
• Encourage activities of parasitoids like Encarsia shafeei or Eretmocerus
mundus
• Release predators Chrysoperla carnea or Coccinella septumpunctata,
Menochilus sexmaculatus, Coccinella septumpunctata or Syrphus
• Avoiding resurgence causing insecticides like Cypermethrin, fenvalerate
and decamethrin
• ETL : 5-10 / leaf (8-10 adults or 20 nymphs/leaf- All India data)
• NSKE 5% or Neem oil 3% along with wetting agent
• FORS (1.4 to 1.5 kg/ha) at early stage
• Biological control: Verticillium lecanii 1.15% WP 2500 g/ha
• Chemical control: Imidacloprid 17.8% SL 100 -125 ml/ha; Thiamethoxam
25% WG 100 g/ha
MANAGEMENT

15. BORERS:
Stem weevil, Pempherulus affinis
F: Curculionidae; O: Coleoptera
Symptoms :
• Swellings of stem at the point of attack (collar region)
• Young plants killed
• Older plants lack vigour and strength
• Plants break off at the point of attack, when heavy winds blow
Grub - White, apodous
Adult - Brownish weevil, 3 mm long, with two small white patches on
elytra

16. Biology
Eggs
Whitish, globular, singly laid in cavities made by weevil at the basal node
(50 eggs / female)
Grub: White, apodous
Pupa: Exarate, in a chamber inside the stem
Adult: Greyish brown, small with white patches
Life cylce : EP : 6-10 d ; LP : 30-40 d; PP : 10-15 d
Management
ETL: 10% stem damage
– MCU 3 – resistant variety
• Basal application of FYM 25 t/ha and 250 kg/ha of neem cake
• Seed treatment with chlorpyriphos 20 EC @ 10ml/kg of seed+ Drenching
collar region with chlorpyriphos 20 EC @ 2.5ml/ l on 15 and 30 DAS+
earthing up
– Carbofuran 3G 30 kg at 20 DAS & earthing up
– Application of FYM 25 t/ NC 250 kg/ha

17. Spotted bollworm, Earias vittella, E. insulana
(Noctuidae: Lepidoptera)
• Widely distributed in North Africa,
India, Pakistan and other countries-
serious pests of cotton
• Punjab- heavy damage to American
cotton
• Host plants
– Okra, hollyhock and some other
malvaceous plants
Damage : larval stage
ETL: 10% square or boll damage

18. Spotted bollworm, Earias vittella; Spiny bollworm,
Earias insulana ; F: Noctuidae; O: Lepidoptera
Symptoms :
• Terminal shoots wither and droop
• Shedding of buds, flowers and bolls, flaring of bracts
• Bore holes on bolls plugged with excreta
• Bolls/fruits eaten and lint/seeds discoloured

19. Spotted bollworm, Earias vittella; Spiny bollworm,
Earias insulana ; F: Noctuidae; O: Lepidoptera
Larva
• Chocolate brown with dorsum
showing a white median
longitudinal streak
E. insulana
• Last 2 thoracic segments and all
abdominal segments have two
pairs of fleshy tubercles (finger
shaped processes)
E. vittella:
• Finger shaped processes absent

20. Spotted bollworm, Earias vitella,
Spiny bollworm, Earias insulana
Adult:
E. vittella:
• Buff coloured small moth, forewings buff coloured with a
green wedge in the middle
E. insulana:
• Buff coloured small moths, forewings uniformly green
Life cycle
EP- 2-3 D ; LP - 10-12 D; PP - 7-10 D

21. Spotted bollworm, Earias vitella
Spiny bollworm
E.insulana

22. Management
• ETL: 10% infested shoots / squares / bolls
– Spraying any one of the following insecticides
– Chlorantraniliprole 18.5% SC 150 ml/ha
– Flubendiamide 39.35% SC 100-125 ml/ha
– Indoxacarb 14.5% SC 500 ml/ha
Biological control:
• Bacillus thuringiensis var kurstaki (3a, 3b, 3c) 5% WP 750- 1000
g/ha

23. Pink boll worm Pectinophora gossypiella
(Gelechiidae: Lepidoptera)
 World most destructive pests of
cotton
 America, Africa, Australia and Asia
 Highly destructive in the Punjab,
Haryana and Pakistan

24. Pink bollworm, Pectinophora gossypiella
F: Gelechiidae; O: Lepidoptera
Symptoms :
• Premature shedding of buds and bolls
• Infested flowers -spun together to form rosette shaped bloom
and boll fails to open
• Premature opening of bolls, burrowing of seeds, seed
germination reduced, poor lint quality, and presence of inter-
locular burrow in the opened bolls

25. Biology
Egg
Flat, singly laid on leaves, flowers, bolls
Larva
Whitish turning pink with fine bands
along the body, undergoes diapause
inside seeds on winter
Pupa
Soil, debris, dry leaves
Adult
Small, dark, active, with black spotted
forewings and fringed hind wings
Life cycle
EP : 4-20 d ; LP : 25-35 ; PP : 6-20 d

26. Pink bollworm, Pectinophora gossypiella …
Larva:
• Initially white, later turn pink with several dark and light
alternating bands running entire length
Adult:
• Small brown moth with black spotted forewings and fringed
hind wings

27. Management
• ETL: 10% infested fruiting parts
• Use pheromone trap to monitor the adult moth activity
• Three weekly releases of egg parasitoid Trichogramma
spp @1,00,000/ha per release coinciding the incidence
of the pest.
• Spraying any one of the following insecticides
– Chlorantraniliprole 18.5% SC 150 ml/ha
– Flubendiamide 39.35% SC 100-125 ml/ha
– Indoxacarb 14.5% SC 500 ml/ha

28. American bollworm, Helicoverpa armigera
F: Noctuidae; O: Lepidoptera
• Distribution: world wide distribution
• Host plants: Polyphagous
Symptoms :
• Regular circular boreholes on bolls/fruits
• Presence of granular faecal pellets outside bore hole
• Larva -seen hanging in bore hole with head and part of
abdomen thrust inside

29. American bollworm, Helicoverpa armigera…

30. BIOLOGY
Egg
Sub-globular, yellowish white with ribs
laid on shoots, buds, bracts tender bolls
4-7 d
Larva
Greenish brown with brownish grey lines
and dark grey yellow stripes on lateral
sides 15-18 d
Pupa
Inside soil, debris 10-14 d
Adult
Stout- yellowish brown with ‘V’ shaped
speck, greyish wavy lines and black mark
on forewings ; Hind wings - whitish with
brown or black border along outer
margin 8-10 d

31. Management
• ETL: One egg or one larva/plant
Monitoring:
• Pest monitoring at farm, village and state level by using light traps,
pheromone traps and in situ assessments by roving and fixed plot surveys.
Cultural practices:
• Synchronised sowing of cotton preferably with short duration varieties in each
cotton ecosystem
• Avoid continuous cropping of cotton both during winter and summer seasons
in the same area as well as ratooning
• Avoid monocropping. Growing of less preferred crops like greengram,
blackgram, soyabean, castor, sorghum etc., along with the cotton as intercrop
or border crop or alternate crop to reduce the pest infestation
• Removal and destruction of crop residues to avoid carry over of pest to next
season, and avoiding extended period of crop growth by continuous irrigation
• Optimising use of nitrogenous fertilizers that will not favour moth
multiplication
• Judicious water management for the crop to prevent excessive vegetative
growth and larval harbourage

32. Biological control:
• Application of Nuclear Polyhedrosis Virus (NPV) at 3 x 1012 POB /ha
in evening hours at 7th and 12th week after sowing
• Bacillus thuringiensis var kurstaki (3a, 3b, 3c) 5%WP 750-1000 g/ha
• Beauveria bassiana 1.15% WP 400 g/ha
• Conservation and augmentation of natural predators and
parasitoids for effective control of the pest.
• Inundative release of egg parasitoid, Trichogramma spp., at 6.25
cc/ha at 15 days interval 3 times from 45 DAS
• Egg-larval parasitoid, Chelonus blackburnii and Predator Chrysoperla
carnea at 1,00,000/ha at 6th, 13th and 14th week after sowing
• ULV spray of NPV at 3 x 10 12 POB /ha with 10% cotton seed kernel
extract, 10% crude sugar, 0.1% Teepol for effective control of
Helicoverpa

33. Chemical control:
• Discourage the indiscriminate use of insecticides, particularly synthetic
pyrethroids
• At early stages of square formation apply one of the following insecticides
• Chlorantraniliprole 18.5% SC 150 ml/ha; Chlorpyriphos 20% EC 1250 ml/ha
• Diflubenzuron 25% WP 300 g/ha; Emamectin benzoate 5% SG 190-220 g/ha
• Spinosad 45.0% SC 165-220 ml/ha; Thiodicarb 75% WP 1000 g/ha
During bolling and maturation stage, apply Quinalphos 25 EC 2.0 l/ha (1000 l
of spray fluid/ha)

34. Integrated pest management of cotton pests
• Remove cotton crop and dispose of the crop residues as soon as harvest is
over.
• Avoid staking of stalks in the field.
• Avoid ratoon and double cotton crop.
• Adopt proper crop rotation. Use optimum irrigation and fertilizers.
• Synchronize the sowing time in the villages and complete the sowing within 10
to 15 days.
• Grow one variety throughout the village as far as possible.
• Avoid other malvaceous crops in the vicinity of cotton crop.
• Timely earthing up and other agronomic practices should be done.
• Hand pick and burn periodically egg masses, visible larvae, affected and shed
squares, flowers and bolls and squash pink bollworm in the rosettes.
• Use locally fabricated light traps (modified Robinson type) with 125 Watt
mercury lamps to determine the prevalence of pests and their population
fluctuation.

35. Integrated pest management of cotton pests ….
• The magnitude of the activity of the moths of the cotton pink bollworm,
the cutworm (Spodoptera litura) and the American bollworm can be
assessed by setting up the species-specific sex pheromone trap each at the
rate of 12 per ha.
• Apply chemical insecticides only when it is absolutely necessary and when
pest population / damage crosses ETL.
• Intercropping with pulses viz., cowpea, greengram, blackgram and soybean
reduce the population of sucking pests of cotton, viz., aphid and leaf
hopper. Also, the bollworm incidence is low. Besides, activity of natural
enemies viz., spiders and predatory lady bird beetles are significant.
• Grow resistant cultivars like G 27, LD 135, Lohit, MCU 7, Sujata, Digvijay