American Cotton Bollworm

Highly polyphagous species attacking 183 host plants which include beans, maize, sorghum, tobacco, tomato, many legumes, some vegetables etc. It causes lot of damage in the field and has developed resistance to several insecticides and is well known all over the world on many crops and may be called as a global pest.

Appearance:

Moths are brownish yellow colored with fore wings having a prominent black spot and a broad black patch on the hind wing margin. Larvae are greenish with longitudinal streaks along the sides of the insect. The color also varies in the grown up larvae which is due to difference in feeding food materials.
            

           Adult                                        Larva 

Life cycle:

Eggs are whitish laid singly on the leaves, squares and flower bracts. Eggs hatch in 3-4 days and the young larvae after hatching feed on several squares, leaves and subsequently attack the bolls feeding by keeping half of its body outside and half inside the bolls (a) with large sized fecal matter on the bolls and leaves (b.) The larval period lasts for about 20-25 days and pupates in the soil and the pupal period is for 8-12 days.     

            (a )                                               (b)                                      Pupa

Nature of damage:

On hatching, the larvae bore into squares, flowers, bolls and locules, usually with their head inserted inside and the remaining part of the body outside.

Damage symptoms:

• Affected squares show “symptoms of flaring up”, with bracts spreading out.
• Internal tissues are hollowed out by the larval feeding, and holes can be seen on squares, bolls or locules.
• In the absence of the squares or after total damage of the squares, larvae can survive by feeding even on the foliage.

           Hole on Boll                             Damaged leaves