Thursday, August 4, 2011

Recommended Insecticides for Cotton Insect Pests


Pest
Insecticide
Qty.of insecticide / ha
Jassids, Aphids, Thrips


Methyl demeton 25 EC
Dimethoate 30 EC
Phosphamidon 100 EC
500 / 750 ml
500 / 750 ml
100 / 250 ml
Whiteflies
Methyl demeton 25 EC
Neem oil + Teepol
Fish oil resin soap
Phosalone 35 EC
500 / 750 ml
3.0 / 3.551 + 500 ml
14 / 15 kg
2.5 / 3.0 litres
Spotted, Pink and
Endosulfan 35 EC
2.5 / 3.0 litres
American bollworms
Chlorpyriphos 20 EC
Quinalphos 25 EC
Monocrotophos 40 EC
Carbaryl 50 WP
Fenvalerate 20 EC
Cypermethrin 10 EC
Decamethrin 2.8 EC
2.5 / 3.0 litres
2.5 / 3.0 litres
2.5 ? 3.0 litres
1.5 / 2.5 kg
400 / 500 ml
800 / 1000 ml
600 / 700 ml
Spodoptera leafworm
Chlorpyriphos 20 EC
Fenvalerate 20 EC
Cypermethrin 10 EC
Decamethrin 2.8 EC
1.5 / 2.0 litres
400 / 500 ml
800 / 1000 ml
600 ? 700 ml
Ash weevil
Aldicarb 10 G
Carbofuran 3 G
10 kg / ha
30 kg / ha
Stem weevil
Drenching stem portion on 20 th & 35 th day with Monocrotophos 40 EC
Phosalone 35 EC
1.5 ml / litre of water

2.0 ml / litre of water
Mite
Dicofol 25 EC
1.5 / 2.0 litres

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