Cotton leaf roller

Systematic position: The Cotton leaf roller (Syllepte derogata) belongs to the order Lepidoptera and the family Crambidae. It is a highly specialized moth species recognized as a significant agricultural pest, particularly in subtropical and tropical agricultural regions where cotton is a primary crop.

Host plants: The primary host of this insect is cotton (Gossypium spp.). However, the larvae are polyphagous within the Malvaceae family and can also infest plants such as hibiscus, hollyhock, and okra, making them a recurring threat in agricultural landscapes and gardens alike.

Biology and life cycle: The life cycle consists of four stages: egg, larva (caterpillar), pupa, and adult moth. Adult moths are primarily nocturnal. Females lay individual eggs on the underside of young leaves. Upon hatching, the larvae immediately begin feeding and use silk threads to roll leaves into protective tubes, where they remain sheltered during their growth stages.

Nature of damage and economic impact: Damage is characterized by leaf folding and skeletonization, where larvae consume the leaf tissue while leaving behind the main veins. In severe infestations, the cumulative loss of leaf area reduces the plant's photosynthetic capacity. This leads to stunted growth, delayed bud development, and significantly reduced yield and fiber quality in cotton crops.

Protection measures: Management of Syllepte derogata requires an Integrated Pest Management (IPM) approach. Cultural practices such as removing infested plant parts and destroying crop residues are essential to reduce overwintering populations. For chemical control, systemic insecticides or biological agents like Bacillus thuringiensis (Bt) are effective when applied during the early stages of larval development to prevent widespread defoliation.