Spotted Bollworm in Cotton

Present in many Old World cotton growing areas. In India Earias insulana is noticed in northern part of the country whereas E. vitella is a common pest in southern region. The pest feeds on alternative host plants like Hibiscus, Holyhock, Sunhemp, China rose, bhendi, pundi, Abutilon indicum etc.

Appearance:

The adults of E. insulana are small; fore wings with uniform silvery green colored whereas E. vittella has buff colored forewing with a green band on the middle of the fore wings. Earias vittella larvae are brownish with longitudinal white stripes on dorsal side having orange dots on prothorax without finger shaped process on the cream colored body. E. insulana has finger shaped process on atleast two thoracic segments and all abdominal segments. Pupa is covered in a boat shaped tough silken cocoon attached to plant parts or on the fallen leaves or fruiting bodies.

                          Earias vittella                           Earias insulana                                Larva

Life cycle:

Females lay about 300 sky blue colored eggs on the young shoot, leaf bracts and squares singly laid, crown shaped, sculptured. Larvae hatch in 3 days and lasts for 10-12 days with a pupal period of 7-10 days completing 20-25 days life cycle.

Nature of damage:

• Caterpillars enter young shoots before the flower bud formation.
• After the square and boll formation, the infestation is noticed on these parts also.

Damage symptoms:

• Drying and drooping of terminal shoots during pre flowering stage
• Side shoots are given out.
• Shedding of squares, young bolls, flaring up of squares during square formation
• Entrance hole on boll is plugged with excreta.
• Affected bolls drop off in early stage and bad boll opening is seen.

             Infested Boll                          Damaged Leaf                   Flaring up of square