Thickened Phyllophaga

Phyllophaga crassissima is a species of beetle belonging to the order Coleoptera and the family Scarabaeidae. Commonly known as one of the May or June beetles, this species is prevalent in North America. These beetles are primarily nocturnal, often attracted to artificial lights, while their larvae, known as white grubs, spend their entire development phase underground.

As a polyphagous pest, Phyllophaga crassissima targets a wide array of crops. The larvae are notorious for feeding on the roots of major field crops, including corn, wheat, and sorghum. Additionally, they cause significant damage to turfgrass, residential lawns, and the root systems of ornamental trees and seedlings grown in plant nurseries.

The biology of this species is defined by a multi-year life cycle, where larvae typically spend one to three years in the soil before pupating. During this time, they migrate vertically through the soil profile based on moisture levels and temperature. This subterranean behavior makes it difficult to detect the infestation until physical damage to the plants becomes irreversible.

The extent of damage is determined by the feeding activity of the grubs. By pruning or completely severing the root system, the larvae prevent the plant from absorbing nutrients and water. Typical field symptoms include yellowing of leaves, stunted plant growth, and patches of dead vegetation where the plants can be easily pulled out of the soil due to the lack of anchor roots.

Effective management requires a combination of strategies. Cultural controls, such as crop rotation and tillage, can significantly reduce larval populations by disrupting their habitat. Chemical control is frequently used, involving the application of granular insecticides or seed treatments. Additionally, integrated pest management (IPM) practices, including the use of entomopathogenic nematodes, are becoming increasingly popular for biological suppression.

• Use of light traps to monitor adult beetle flight activity.
• Deep autumn tillage to expose larvae to birds and frost.
• Seed treatment with systemic insecticides.
• Application of granular insecticides at the time of planting.