Marble cockchafer

The Marble cockchafer (lat. Polyphylla alba) is a large beetle belonging to the family Scarabaeidae within the order Coleoptera. It is named for the distinctive marble-like pattern on its elytra, created by dense white scales. This pest is specifically associated with sandy soils, where it thrives and causes significant problems for horticulture and forest nursery management.

It is the larval stage that causes the most severe damage to agricultural crops and trees. The larvae develop in the soil over a period of three to four years, gradually increasing in size and appetite. While the adult beetles feed on pine needles and tree leaves, the underground larvae cause devastation by severing roots, which leads to the immediate decline of the host plants.

The biological cycle is complex and spans several years. Female beetles deposit eggs deep into the sandy substrate. Upon hatching, the larvae go through several instars. They begin by consuming organic matter but eventually transition to feeding on the succulent root systems of young trees, perennial vines, and various vegetable crops, burrowing through the soil.

The damage caused by the Marble cockchafer is often visually characterized by the sudden wilting of plants, which occurs because the root system is unable to provide water and nutrients to the aerial part. Economically, this pest is a major threat in sandy zones where it can destroy vast areas of new plantings, making it essential to identify its presence early.

• Deep plowing and tillage to expose larvae to birds and drying out.
• Soil application of synthetic insecticides targeting subterranean stages.
• Use of entomopathogenic fungi as a biological control measure.
• Planting repellent green manure crops like lupine or mustard.
• Trapping adult beetles during their peak flight period to reduce egg deposition.