Cotton Spotted bollworm | Top 8 Management

(Cotton Spotted bollworm, Nature of damage, life cycle, egg stage, larval stage, pupa stage, adult stage, Top 8 Management, Natural enemies)

If you do cotton farming. And if the Cotton spotted bollworm is harming your crop in your field, then today we will know in this article the scientific name, life history of spotted bollworm on cotton, and how to control this insect.

Cotton Spotted bollworm 

The local name of Cotton Spotted bollworm is Cittkabri Surhi. 

Nature of damage of Cotton Spotted bollworm 

The larval stage causes significant damage to the crop.

• The larva is the destructive stage of pests which in the beginning (when plants are small 20 to 30 cm height) Bore the top portion of the growing shoot which winters and drop have a result of which plant growth is adversely affected.
• Lefroy (1906) stated that this pest is more serious than locusts. When the flower buds and bolls appear, the larvae start feeding on them.
• The caterpillars bore into bolls and close the hole with their excreta and feed inside the attacked bolls are generally shed and those left on the plants open prematurity with that result the poor quality of fibre is produced and market value is reduced.
• Severe holes plugged with excreta can be seen on the bolls and a single Larva may destroy many bolls in its lifetime.
• The damage caused by the best is estimated to the turn of 22 – 50% by Clainston (1921), and 50% by Mishra (1938). its ETL is a 10% attack on fruiting parts.

The life cycle of cotton Cotton Spotted bollworm 

A spotted bollworm occurs in four developmental stages, its cycles being egg, larva, pupa, and adult.

The egg stage of Spotted bollworm

This is the first developmental in which a female lays eggs.

• The female moth lays generally singly scattered over fresh squares.
• The eggs are spherical, blueish green in colour with parallel longitudinal ridges which project upwards and give it a crowned appearance.
• The female lays 200 to 500 eggs in her lifetime only at night.
• An individual egg is 1 mm in diameter.
• The hatching period of eggs varies from 3 to 4 days in summer and 8 to 9 days in winter.

The larval stage of Spotted bollworm

is the second developmental stage of the life cycle of Spotted bollworm.

• The newly hatched Larva is brownish-white with a dark head and prothoracic shield. It measures 1.2 to 1.3 mm in length.
• The caterpillar remains about 24 hours outside the shoot or bolls and after that, it enters into the shoot or boll.
• The larva moults 34 or becomes full-grown measuring 22 to 25 mm long.
• The caterpillar of E.nutella is brown with a medium longitudinal streak while E.insulana has a dull green body with several black marks and oval orange dots on the prothorax.
• The caterpillar becomes fully grown in 10 to 12 days during summer and 15 to 20 days during winter.

The pupa stage of the Spotted bollworm

is the third developmental. Its pupation process takes place in the soil.

• The full-grown caterpillar comes out of the boll and pupates either on the plant or the ground among fallen leaves or 5-25 CM deep in the soil.
• The pupa is enclosed in a tough silken cocoon of dirty white or light brown colour.
• Its pupa is 12 mm long and 4 to 5 mm wide.
• The pupal period of spotted bollworm ends in 5 to 15 days in the summer and rainy seasons. Whereas in the winter season it ends in 18 -31 days.

The adult stage of the Spotted bollworm

This is the final developmental stage of the Cotton Spotted bollworm

Earias xitella 

The moth measures 12 mm long and 21mm across the wings; the forewings have a broad green band extending from the base to the apex and the hind wings are white.

The body is pinkish-white in color having a tuft of hairs behind the thorax.

Earias insulana

It measures about the same as above but now that wings are completely clean the species is more prevalent in dry regions.

The pest remains active throughout the year but the population is very low from December to March.

It begins to multiply in April-May and reaches its maximum during July – September.

The life cycle is completed in 31 to 55 days and 7-8 generations are found in a year; the males die after copulation; females survive 10 to 20 days depending upon the season.

Top 8 Management of Cotton Spotted bollworm

If you want to control Cotton Spotted bollworms in the sugarcane field, then you can manage it by using the methods given below.

• Destruction of plants that harbour the pest 
• After harvesting crops the field should be ploughed to destroy the hidden caterpillars.
• Collection and destruction of infested shoots and bolls.
• The crock may be expressed with any one of the following insecticides to minimize the attack of pests.

2. Endosulfan 35 EC @ 2.5 litre/hectare
3. Thiometon 25 EC @ 1.25 liter / ha
4. Fenitrothion 50 EC @ 3.00 liter /ha
5. Quinalphos 25 EC @ 2.0 liter /ha
6. Carbaryl 50 WP @ 2.5 kg /ha

• The crops should be sprayed twice, first at hatching the eggs (peak hatching period) and second after 15 days of the previous spraying.
• The quantity of water may be required 700 – 750 liter/ha 
• The insecticides to be applied on Okara crop Endosulfan or DDVP should be preferred.

Natural enemies of Cotton Spotted bollworm

The following are the natural enemies on different stages of the pest.

Egg Parasite

• Trichogramma chilonis
• Larval parasite
• Microbracon lefroyi D and G
• Microbracon hebets say
• Elasmus sp

Pupal parasite

• Melch mursei carn
• Chelonia Rufus Lyle
• Chalchis sp

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