Insects

Pests On Cotton – Pest Affects the cotton – Study material

PESTS ON COTTONCotton Aphid,  Aphis gossypii (Aphididae : Hemiptera)

  • World wide, potential pest – Highly polyphagous, wider host range 
  • Nymphs and adults desap on young crop in colonies.
  • Tender leaves curl up, reduced in size, gradually fade and dry up. 
  • Plant growth severely shunted. Leaves show oily appearance 
  • Sooty mould develops on honey dew on lower leaves
  • Ants are seen moving briskly on plants 
  • Adults and nymphs are yellowish / greenish brown in colour. Alate and apterous forms are seen. Reproduce parthenogenetically and are viviparous. 
  •  Life cycle – 7-9 days

Leaf hopper/ jassid,   Amrasca devastans Cicadellidae : Homoptera
  • Damage on young seedlings may be 80-100%. 
  • Hosts: Bhendi, hollyhock, brinjal, potato, mesta, sunflower, cucurbits. 
  • Dry conditions in early stages favour the pest. 
  • Adults- greenish / greenish yellow. wedge shaped 
  • Nymphs- Initially pale yellow turning green slowly.  Eleven generations in a year is observed.  
  • Symptom: Toxemia (by injection of saliva into plant tissues by nymphs and adults) resulting in hopper burn.
  • Initially leaf margins turn pale green, yellow and finally brick red or brown. 
  • Leaves become crinkled and curled resulting in complete drying and dropping of leaves. Plants stunted. Number of flowers, bolls, seed weight, and quality of lint reduced. 
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Thrips, Thrips tabaci, Scirtothrips dorsalis (Thripidae : Thysanoptera)
  • Hosts :  Bhendi, Chillies, brinjal, onion, tomato, sunflower, mango, citrus, tea 
  • T. tabaci – on flower ; S. dorsalis – on leaves 
  • Nymphs and adults lacerate tissues, desap .
  • Leaves shrivel with ragged edges, brittle, fall off mal formed- Silvery metallic sheen on leaf under surface 
  • Adults, small, yellowish or brown with fringed wings ; Nymphs – minute, slender yellowish. Life cycle:  EP: 2-3 d; NP: 5-8 d; PP: 3-5 d.
WhiteflyBemesia tabaci Aleyrodidae: Hemiptera
  • Serious pest on cotton whenever synthetic pyrethroids are indiscriminately used. Highly polyphagous 
  • Hosts:  Tobacco, Cassava, bhendi, hollyhock, safflower, sunflower etc.,
  • Nymphs found in colonies on leaf under surface and desap. 
  • Leaves turn chlorotic, drop down, Sooty mould, Reduced vigour, boll-shedding, buds, flowers, improper boll-bursting. 
  • vector of Cotton leaf curl disease 
  • Adult- Small, moth like with white hyaline wings dusted with white powdery scales, body yellow. Nymphs : Green-on leaf undersurface. 
  • 10-12 generations / year 

Red Cotton bug / StainerDysdercus civigulatus (Pyrrhocoridae :  Hemiptera)
  • Nymphs and adults desap on tender unopen bolls
  • Tender bolls show microscopic punctures 
  • Boll opening erratic 
  • Bacterium, Nematospiora gossypii stains lint Yellow 
  • Seeds unfit for sowing and oil extraction 
  • Adult: Medium sized, black markings on hemielytra with a black spot – long antenna. Adults – hibernate in winter 
  • Life cycle : EP : 4-7 d ; NP : 50-90 d (5 instars)


Dusky cotton bug, Oxycarenus hyalinipennis  (Lygacidae : Hemiptera)
  • Damage at boll-bursting stage 
  • Nymphs and adults are dusky brown 
  • Desap seeds at boll burst in small groups 
  • Seeds shrivel, shrunken, Lint stained black 
  • Adult :  Small, flat with dark brownish black body and transparent wings 
  • white eggs – laid in clusters of 2-10 inside half-opened bolls, on the bolls, flowers or buds.   
  • Nymphs : Five instars. Life cycle 30-40 days

Spotted bollwormsEarias vitella, E. insulana (Noctuidae : Lepidoptera)
  • Incidence starts 40-50 DAS. Potential pest of cotton 
  • Bolls with irregular bore holes smeared with excreta, 
  • Dropping of bolls, irregularly bored Lint 
  •  Larva bores tender shoot-causing dead hearts drooping and drying of shoot tips 
  • At square formation, bores squares causing flaring and dropping of squares 
  • Pupa: Boat shaped leathery cocoon on buds, bolls or debris 
  • Life cycle: EP: 3-4 d; LP: 10-12 d; PP : 7-10 d.  
  • E. vitella: Small moth forewings yellow with green band. Hind wings yellow / hyaline 
  • Larva: brown with white median longi stripe and no finger-like processes 
  • E. insulans : forewings – totally green 
  • Larva: more creamy with small finger – shaped processes (on 2, 3 Thorax  and abdomen) and orange dots on prothorax 


Pink BollwormPectinophora gossypiella (Gelechiidae : Lepidoptera
  • Damage:  85-100% 
  • Premature shedding of buds, bolls 
  • At flowering – Rosette bloom- Petals are webbed together without opening.  
  • Inside the Rosetted flowers yellowish white larva devours style, anthers and ovary
  • Bore-holes will not be seen outside as the young larva enters the boll through the tip which heals up
  • Premature opening of bolls exposing lint to saprophytic fungus – reducing ginning qualities
  • Inside the bolls, seeds and locules are damaged 
  • larva bores adjacent seeds to form double seeds for hibernation
  • Lint stained
  • Larva: Young ones pale yellow , before pupation attain pink colour 
  • Pupate in soil among fallen leaves, flowers, clods.  
  • Moth:  Small, active, dark brown, dull yellow or live grey with dark spots on forewing.  
American Bollworm/ Gram pod borer Helicoverpa armigera (Noctuidae : Lepidoptera)

  • Tender buds, bolls attacked, flaring squares 
  • Young larvae feed on foliage causing irregular holes 
  • On bolls, round holes are seen
  • Larva  cannibalistic
  • Green larva thrusts – head alone inside tail outside 

Stem weevilPhempherulus affinis (Curculionidae : Coleoptera)
  • Severe pest on summer cotton. Damage in young seedlings 60-80% 
  • Plants suddenly wilt and dry up.At collar region galls seen 
  • Plant tend to break at the collar region, Gall – result of phytotoxaemia  
  • Yellowish white grub / pupa or small brown weevil seen inside tunnels
  • Adult, small snouted brown weevil. Grubs fleshy, yellowish white, feeding on tissues. Pupa :  inside the chamber on stem 

Semi loopers 
  • Larvae feed on foliage causing irregular feeding holes 
  • Crop becomes sickly with stunted growth with reduced squares, bolls, flowers 

Anomis flava Medium, forewings reddish brown with brown  spot and faint cross stripes. Males brighter. Larva: Green with 5 longitudinal stripes red prologs.
Acontia graellsi  Medium, forewings lemon yellow with transverse brown streak and Larva: Green with brown horse-shoe shaped markings and black warts 
Tarache nitidula Adult:  White wings with dark markings. Larva:  Dark brown 
Leaf Roller : Sylepta derogate (Pyraustidae : Lepidoptera)


  • Larva rolls the leaves and feed within leaves dry and drop, trumpet-shaped rolls 
  • Results in total defoliation 
  • Moth :  Medium, whitish, yellow with brown wary markings
  • Larva : Green, glistening, brist-moving scrapping and feeding leaves – sparse hairs. Pupa  : Within leaf fold / debris in ground 

Tobacco caterpillarSpodoptera litura (Noctuidae : Lepidoptera)  

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