Northern corn rootworm

Systematic position: The Northern corn rootworm (Diabrotica barberi) is a member of the order Coleoptera, family Chrysomelidae. It is a significant agricultural pest that specifically targets corn crops, often overlapping in distribution with other rootworm species, requiring careful identification for effective management.

Crops and economic impact: The primary host is corn. The larvae cause the most significant damage by feeding on corn roots, which hinders water and nutrient uptake. This structural damage can result in severe lodging, where corn stalks lean or fall over, making harvesting difficult and causing substantial yield losses. Adult beetles damage reproductive structures, reducing fertilization rates.

Biology and life cycle: This pest has one generation per year. Eggs are laid in the soil during the late summer and overwinter until spring. Larvae emerge and immediately seek corn roots. After pupating in the soil, adults emerge in mid-to-late summer. They are known for their ability to disperse and locate new corn fields for oviposition.

Nature of damage: Larval feeding often leaves root systems pruned or completely destroyed. Severely infested fields exhibit uneven growth and "goose-necking" of stalks. Adult feeding on silks during pollination can prevent ear filling, leading to poorly developed ears and lower grain quality, which directly impacts the profitability of the corn operation.

Protection measures: Management of the Northern corn rootworm requires a multi-faceted strategy:

• Crop rotation is the most effective cultural practice, as larvae cannot survive on non-corn crops.
• Use of soil-applied insecticides at planting time to protect the developing root system.
• Monitoring adult beetle populations using sticky traps to determine the necessity of insecticide applications.
• Planting genetically modified corn hybrids expressing proteins toxic to rootworm larvae.