Pine chafer

The pine chafer (Polyphylla fullo) is a large beetle belonging to the family Scarabaeidae within the order Coleoptera. It is easily recognized by its distinctive mottled white and brown pattern on its wing covers, which resembles marble. These beetles are primarily nocturnal and are often attracted to artificial lights during warm summer nights.

The damage caused by this insect is divided between adult feeding on needles or leaves and, more significantly, root consumption by its larvae. The larvae, also known as white grubs, pose a major threat to agricultural and forestry crops. They are particularly attracted to sandy soils, where they cause extensive damage to the roots of young trees, vines, potatoes, and various vegetable crops.

The life cycle of the pine chafer is extended, typically spanning three to four years. The larvae spend most of their existence underground, feeding initially on decaying organic matter before switching to live roots as they mature. Their development is slow, and they go through several larval instars, with the later stages being capable of causing severe damage to established plants.

Larval feeding manifests as severed roots and chewed root collars, which prevents the plant from absorbing nutrients and water, eventually leading to rapid wilting and death. Large infestations can result in the loss of significant portions of seedlings in forest nurseries or orchards, making early detection and prevention vital for agricultural success.

Integrated pest management (IPM) is essential for controlling the pine chafer:

• Mechanical cultivation of soil, such as plowing and harrowing, to expose larvae to natural predators like birds.
• Application of soil-incorporated insecticides during planting to provide a chemical barrier.
• Use of biological control agents, including entomopathogenic fungi like Beauveria bassiana or nematodes that target larval stages.
• Monitoring adult beetle activity with pheromone or light traps to determine timing for potential intervention.