Sudanese cotton bollworm

The Sudanese cotton bollworm (Diparopsis tephragramma) is a significant pest belonging to the order Lepidoptera and the family Noctuidae. It is recognized as a specialized insect that poses a serious threat to cotton cultivation in specific geographical areas within Africa.

This species primarily attacks plants of the genus Gossypium. The larvae are notorious for feeding exclusively on the reproductive parts of the cotton plant, specifically targeting flower buds, blossoms, and the developing bolls, which are essential for commercial yield.

The biology and lifecycle of the pest are synchronized with the growth stages of the cotton plant. Eggs are deposited on various parts of the plant, and upon hatching, the larvae quickly bore into the floral buds or internal tissues of the bolls. The species typically produces several generations throughout the growing season, enabling it to maintain a high population density.

The economic damage is severe, as larval feeding directly reduces the number of harvestable bolls. Beyond the mechanical damage, the entry holes created by the larvae serve as entry points for pathogens, leading to boll rot and premature shedding of the fruiting structures, which drastically reduces the total yield and fiber quality.

Integrated Pest Management (IPM) is essential for effective control of Diparopsis tephragramma. Key strategies include:

• Crop rotation to break the pest's lifecycle.
• Monitoring pest populations using pheromone traps.
• Timely application of selective insecticides before larvae penetrate the bolls.
• Encouraging natural predators and parasitoids in the field environment.

Maintaining high standards of agronomic practice, such as removing crop residues after harvest, is also crucial to reduce the population of overwintering pupae in the soil and mitigate risks for the subsequent planting season.