Garden chafer

Systematic position: Anomala dubia, commonly known as the garden chafer or shining leaf chafer, belongs to the family Scarabaeidae within the order Coleoptera. This species is a recognized pest across European and Asian regions, capable of causing significant economic losses in horticulture, forestry, and agriculture.

Affected crops: Adult beetles feed on the foliage of a wide range of broad-leaved trees and shrubs, including fruit trees like apple and pear, as well as grapevines. In their larval stage, these insects reside underground and consume the roots of grasses, vegetable crops, young ornamental plants, and nursery seedlings, often causing severe physiological damage to the host.

Biology and life cycle: The insect typically completes its life cycle over two years. Adults emerge in early summer, often exhibiting high activity during warm, sunny weather. Females lay their eggs in moist, organic-rich soil. The larvae undergo three instars, spending two winters in the soil at considerable depths before pupating in the spring of their second year.

Nature of damage and pest status: Adult beetles create irregular holes in leaves, often skeletonizing them when populations are high, which drastically reduces the vigor of the trees. The larvae are particularly destructive as they prune the root systems, leading to wilting, stunted growth, and eventual death of the affected plants, which creates gaps in crops and lawns that are difficult to recover.

Effective management and control of Anomala dubia rely on a combination of cultural and chemical strategies designed to interrupt the life cycle:

• Tilling and cultivating the soil during late spring or autumn to disrupt the larvae and expose them to natural predators like birds.
• Foliar application of insecticides during the peak activity period of the adult beetles to protect the canopy.
• Biological control through the application of entomopathogenic nematodes or fungi, which target the soil-dwelling larvae.
• Monitoring adult population density using light traps to determine the optimal timing for protective measures.