Oak acorn weevil

Systematic position. Pterocolus ovatus is a species of weevil belonging to the order Coleoptera and the family Rhynchitidae. It is a specialized insect that plays a significant role in the seed ecology of oak forests, often acting as a key pest for reproductive parts of the trees.

Host plants and economic impact. The primary hosts are oak trees (genus Quercus). The economic impact is concentrated on the reduction of viable seeds, which is critical for natural regeneration and reforestation efforts. By infesting acorns, the weevil significantly decreases the germination success rate in both natural forests and nurseries.

Biology and life cycle. The life cycle is synchronized with the development of the host plant. Adults emerge in late spring or early summer to mate. The female drills a hole into the young acorn, oviposits, and then weakens the peduncle to cause the acorn to drop. The larva completes its development inside the fallen acorn, feeding on the cotyledons before burrowing into the soil to pupate.

Damage patterns. The most noticeable symptom of an infestation is the premature drop of green acorns during the summer. Upon inspection, these acorns contain internal tunnels and frass produced by the larvae. Infested seeds become hollow or degraded by secondary fungal infections, which prevents them from establishing new seedlings.

• Collection and destruction of infested fallen acorns to break the pest cycle.
• Cultivation of the soil under the tree canopy to expose pupae to predators and winter conditions.
• Targeted use of systemic insecticides in nursery settings during the adult activity peak.
• Maintaining biodiversity to support natural predators, such as parasitic wasps and birds.