Cotton stem weevil

Eutinobothrus puncticollis is a significant agricultural pest belonging to the Curculionidae family within the order Coleoptera. It is widely recognized as a specialized pest of cotton, primarily causing severe damage in various South American countries, where it poses a constant threat to cotton productivity and fiber quality.

The primary host for this pest is the cotton plant (Gossypium spp.). Unlike other weevils that attack bolls or squares, Eutinobothrus puncticollis larvae specialize in boring into the stems and the root collar of the plant. This feeding behavior disrupts the transport of water and nutrients, severely weakening the plant structure and often leading to plant death.

The life cycle of the cotton stem weevil is intrinsically linked to the development of the host plant. Female weevils lay their eggs in the stems, where the developing larvae spend their entire feeding stage. This internal development makes the pest highly protected from natural predators and environmental stressors, complicating conventional control methods.

Damage symptoms include wilting of the plant tops, stem deformation, and the formation of galls at the site of larval infestation. The presence of the pest is often detected too late when the internal structural damage is irreversible. Persistent infestations result in significant reductions in plant vigor, leading to substantial economic losses for cotton growers.

Integrated Pest Management (IPM) is essential for controlling this pest. Recommended practices include:

• Destroying infested crop residues after harvest to reduce overwintering populations.
• Implementing strict crop rotation programs to break the pest cycle.
• Applying systemic insecticides during the peak activity of adult weevils.
• Using trap crops to divert adult weevils from the main cotton fields.