Northern masked chafer

The Northern masked chafer (Cyclocephala borealis) is a beetle species belonging to the family Scarabaeidae. Unlike other scarab beetles, it does not possess a horn on its head. Adult beetles are roughly 12 to 14 mm long with a straw-colored to yellowish-brown appearance. The larval stage, often referred to as white grubs, causes significant damage while living in the soil.

This pest is primarily recognized for damaging turfgrass, such as lawns, golf courses, and pastures. However, it can also affect agricultural crops, including corn and various small grains. By feeding on the root systems of these plants, the grubs disrupt water and nutrient uptake, leading to yellowing, stunted growth, and eventual death of the affected vegetation.

The life cycle of the Northern masked chafer typically spans one year. Adults emerge during the summer months for mating and egg-laying, choosing areas with dense vegetation. The larvae hatch and progress through three instars, feeding voraciously on roots until the soil temperature drops in the autumn, at which point they descend deeper into the soil to overwinter.

Damage is often identified by large brown patches of turf that can be easily peeled back from the soil like a carpet, as the roots are completely severed. In addition to the direct physiological damage caused by the larvae, secondary damage is frequently observed from birds, skunks, and raccoons foraging for the grubs, which causes even more disruption to the landscape.

Integrated Pest Management (IPM) strategies for the Northern masked chafer include:

• Regular soil monitoring in late summer to detect larval density.
• Applying preventive or curative insecticides targeting the larval stage.
• Utilizing beneficial biological agents such as entomopathogenic nematodes.
• Maintaining healthy, robust turf through proper fertilization and watering practices.
• Avoiding excessive use of nitrogen fertilizers that may attract egg-laying adults.