Polyphylla olivieri

Polyphylla olivieri is a member of the order Coleoptera and the family Scarabaeidae. This beetle is a significant pest known for its large size and characteristic, striped appearance on the elytra. Native to regions in the Middle East and surrounding territories, it poses a recurring challenge to fruit growers and nursery owners due to the subterranean nature of its larvae.

This beetle is a polyphagous pest, meaning it attacks a wide variety of plants. It predominantly affects orchards, including apple, pear, and stone fruit trees, as well as grapevines. Additionally, the larvae are known to damage the root systems of various cereals, vegetables, and ornamental trees, often leading to stunted growth or total crop failure in heavily infested agricultural areas.

The life cycle of the beetle is long and complex, usually spanning several years. The developmental stages occur almost entirely underground, where the larvae live and feed on roots. As they grow through several instars, their appetite increases significantly, and they become capable of causing substantial structural damage to the root systems of even well-established trees.

The damage is primarily subterranean, making it difficult to detect until symptoms such as wilting or chlorosis appear on the foliage. Once the roots are severely pruned by the larvae, the plant becomes susceptible to secondary infections and environmental stress. In cases of high population density, young orchards can suffer complete mortality within a single growing season.

Effective management requires an integrated approach to break the pest's life cycle. Control strategies include:

• Deep tillage to disrupt the larvae in the soil profile.
• Applying systemic or contact soil insecticides during planting.
• Utilization of biological control agents, such as entomopathogenic nematodes or fungi.
• Implementing light traps during the adult flight season to monitor population trends and reduce the number of egg-laying females.