Major Insect-Pest Of Cotton
- Cotton jassid: Amrasca biguttula
F:Cicadelidae O: Hemiptera.
- Destructive pest of American cotton
- Nymphs – wedge shaped
- Adults – winged form.
Symptoms:
- Adult and nymph cause injury to crop because of loss of sap and probably also due to the injection of toxins.
- Yellowing and downward rolling/cupping of leaves .
- Cotton whitefly: Bemisia tabaci
F:Aleyrodidae O: Hemiptera
- The pale yellow body is slightly dusted with a white waxy powder.
- They have two pairs of pure white wings and have prominent long hind wings.
Symptoms: damage done by two types.
- The vitality of the plants is lowered through the loss of cell sap.
- The normal photosynthesis is interfered due to the growth of a sooty mould on the honey dew excreted by the insects.
- It transmit a number of viral disease including the leaf curl disease of tobacco, vein curling disease of okra and leaf curl of sesame.
Management:
- Jassids and whiteflies can be effectively managed by spraying of Imidacloprid 200 SL @ 75 g a.i. /ha or Thiomethoxam @ 45 g a.i. /ha.
- Spray of Dimethoate @ 1 ml/liter of water
Major Insect-Pest Of Cotton
- Pink boll worm: Pectinophora gossypiella
F:Gelechidae O:Lepidoptera
- Most destructive pest of cotton.
- The caterpillars are pink in colour and found inside the flower buds, panicles and the bolls of cotton.
Symptoms:
- Damage done by caterpillar in various ways there is excessive shedding of the fruiting bodies.
- “Rosette flower” is characteristic symptoms.(IARI, Ph. D-09)
- Total shedding is caused by all the boll worms.
- Double seed formation: The two adjoining seed are joining together within damaged boll by pink boll worm.
- Spotted boll worm: Earias insulenalvitella
F:Noctuidae O: Lepidoptera.
- It is serious pest of cotton and okra.
- A series of longitudinally black spots on the body with dull green colour
- and having tiny stout bristles are the main identification mark of spotted boll worm.
Symptoms:
- Cause heavy shedding of fruiting bodies.
- ‘Flare square’ (Flare-up) is characteristic symptoms. (JRF-07)
- Attacked bolls the lint is spoiled cause of larval feeding.
- The infected bolls open prematurely and produce poor lint resulting in lower market values
Management:
- Growing of Bt. cotton varieties is the effective method for boll worm complex.
- Destruction of cotton sprouts, alternative host plants or burning of the plant debris.
- Deep ploughing (with furrow turning plough) done by the end of February.
- Larval: Parasitoid Bracon greeni, Chelonus pectinophorae.
Other pests of cotton:
1.Dusky cotton bug: Oxycarenus laetus
F:Lycaenidae O: Hemiptera.
2.Red cotton bug: Dysdercus singulatus
F:Pyrrhocoridae O: Hemiptera.
- Effected quality of lint.
3.American boll worm: Helicoverpa armigera
F:Noctuidae O: Lepidoptera.
4.Cotton leaf roller: Sylepta derogata
F:Pyralidae O: Lepidoptera.
