Folded weevil

The folded weevil (Rhytidoderes plicatus) is a beetle belonging to the Curculionidae family. It is recognized by its distinctively wrinkled and folded elytra. This insect is a significant specialist pest that primarily targets crops belonging to the Brassicaceae family, making it a constant concern for commercial vegetable and oilseed producers.

The host range of this pest includes various types of cabbage, rapeseed, radishes, and turnips. Both adults and larvae contribute to the damage. While adult beetles typically feed on the foliage, causing ragged holes, the larvae are often more destructive as they bore into the roots and stems, directly impacting the nutrient transport system of the plant.

Regarding its biology, the insect typically overwinters in the adult stage within the soil or debris. As temperatures rise in the spring, the beetles emerge and begin feeding. Females deposit eggs in or near host plants. The subsequent larval development occurs within the plant tissues, followed by pupation, which usually takes place in the soil, completing the life cycle.

The economic impact of Rhytidoderes plicatus is manifested by stunted growth, wilting, and potential plant death if the infestation is heavy, especially during the seedling stage. Adult feeding reduces the photosynthetic capacity of the plants, while larval tunnelling weakens the physical structure, often leading to total crop failure in extreme cases.

Integrated Pest Management (IPM) strategies are essential for control.

• Crop rotation is the most effective cultural practice to break the life cycle.
• Sanitation measures, including the removal of cruciferous weeds.
• Monitoring populations during the early growth stages.
• Applying targeted insecticides when thresholds are exceeded to protect the crop during the most vulnerable periods.