Two-spotted weevil

Systematic position. The two-spotted weevil (Notaris bimaculatus) belongs to the order Coleoptera and the family Curculionidae. This species is commonly found in wetland ecosystems, often associated with marsh vegetation and specialized plant communities in moist soil environments.

Affected crops and damage. While its primary hosts include Typha species, this weevil can occasionally migrate to agricultural crops grown in proximity to riverbanks or reclaimed peatland soils. The larvae are the primary source of economic damage, as they feed internally on stalks and rhizomes, compromising the structural integrity of the plant.

Biology and life cycle. This pest undergoes complete metamorphosis, consisting of egg, larval, pupal, and adult stages. The adult weevils hibernate in the topsoil or under dense leaf litter during the winter. Once temperatures rise in early spring, the adults emerge to feed and begin the reproductive cycle, depositing eggs into the plant tissue.

Damage patterns. Adult weevils feed on leaves, leaving distinctive notched edges. The larvae, however, cause significant harm by tunneling into stems, where they consume the pith. This boring activity disrupts nutrient transport and often causes the plant to wither or collapse, particularly when infestations reach high densities.

Protection measures. Effective management relies on cultural practices such as maintaining field edges free from alternative host weeds and ensuring proper drainage of agricultural fields. During severe outbreaks, the application of registered insecticides is recommended. Integrated pest management (IPM) should prioritize early monitoring to prevent larval establishment within the plant stems.