Insect pest of cotton and their symptoms of damges

Insect pest	Scientific name	Symptoms of damage
Sucking pests
Jassids	Amrasca biguttula biguttula	Affected leaves curl downwards, turn yellowish, then to brownish before drying and shedding, "hopper burn" stunts young plants
Aphids	Aphis gossypii	Leaf crumpling and downward curling of leaves, sticky cotton due to deposits of honey dew on open bolls
Thrips	Thrips tabaci	Leaves of seedlings become wrinkled and distorted with white shiny patches, older crop presents rusty appearance from a distance
Whiteflies	Bemisia tabaci	Upward curling of leaves, reduced plant vigour, lint contamination with honey dew and associated fungi, transmission of leaf curl virus disease
Bollworms
Spotted & spiny bollworms	Earias vitella & E.insulana	Boremark in main shoot, dried and withered away shoot, twining of main stem due to axillary monopodia, feeding holes in flower buds and bolls blocked by excrement
American bollworm	Helicoverpa armigera	Small amount of webbing on small squares injured by young larvae, squares have a round hole near the base, larval frass and flaring of bracts on larger squares, clean feeding of internal contents of bolls, excessive shedding of buds and bolls
Pink bollworm	Pectinophora gossypiella	"Rosetted" bloom, pink larvae inside developing bolls with interloculi movement
Stainers
Red cotton bug	Dysdercus cingulatus	Feed on developing and mature seeds, stain the lint to typical yellow colour, reddish nymphs seen in aggregations around developing and open bolls
Dusky cotton bug	Oxycarenus hyalipennis	Associated with ripe seeds, all stages characterized by a powerful smell, discolour the lint f crushed
Foliage feeders
Semi - looper	Anomis flava	Causes significant loss of leaf area to young plants, larvae with looping action are seen on plant parts.
Leaf roller	Syllepte derogata	Leaves are folded and larvae are seen in groups amidst fecal materials, commonly seen on leaves at the bottom of crop canopy at low infestation levels, severe infestation defoliates the whole plant
Spodoptera leafworm	Spodoptera litura	Young larvae in groups skeletinise leaves and older larvae voraciously defoliate leaves
Grey weevil	Myllocerus subfasciatus	Marginal notching - off of leaves
Grass hopper	Crytocanthacris ranacea	Defoliation of leaves - partial or full
Root / Stem feeder
Stem weevil	Pempherulus affinis	Root damage by grubs kills young seedlings, gall like swelling seen on lower stem, wilting of seedlings