Transcaucasian chafer

Systematic position. The Transcaucasian chafer (Polyphylla perversa) belongs to the order Coleoptera and the family Scarabaeidae. It is a significant pest known for its large size and the destructive feeding behavior of its larvae, which live in the soil and attack various plant roots throughout their extended life cycle.

Host plants and damage. This beetle is a polyphagous pest, meaning it attacks a wide range of plants. It is particularly dangerous to the root systems of young fruit trees, vineyards, berry bushes, and field crops such as potatoes and corn. Infestations in nurseries can lead to catastrophic losses if left unmanaged.

Biology and life cycle. The life cycle of Polyphylla perversa spans several years, with most of the development occurring underground. Adults emerge to feed on tree foliage and mate, after which females deposit eggs deep in the soil. Upon hatching, larvae spend several years feeding on organic matter and living roots before pupating in deep soil chambers.

Nature of damage. Larvae, especially in later instars, are extremely destructive due to their robust mouthparts. They sever roots near the base, preventing the plant from absorbing necessary water and nutrients. This damage often results in stunted growth, yellowing foliage, wilting, and eventual death of the affected plant.

Control measures. Effective management involves a combination of preventative and curative strategies to reduce the population density of the larvae:

• Deep plowing or mechanical tillage to expose larvae to birds and drying conditions.
• Application of soil-incorporated insecticides at the time of planting or high-risk periods.
• Use of biological control agents like entomopathogenic fungi or nematodes.
• Regular soil monitoring to identify and treat infestations before they spread.