Hydrobia

Systematic position: Hydrobia (Hydrobia) is a genus of small operculate snails belonging to the phylum Mollusca, class Gastropoda, order Littorinimorpha, and family Hydrobiidae. These mollusks are often considered pests in aquatic nurseries, aquaculture systems, and flooded rice cultivation, where they thrive in nutrient-rich aquatic environments.

Affected crops and damage: The primary hosts include various aquatic ornamental plants and young rice seedlings. By grazing on tender leaf tissues and stems, Hydrobia can drastically reduce plant stand density. In aquatic farming, they consume essential biomass, which often leads to the destruction of young aquatic vegetation and creates significant economic losses for producers.

Biology and life cycle: The life cycle of Hydrobia is strictly aquatic. They deposit eggs on submerged surfaces, such as plant stalks, stones, or debris. Development is direct, allowing for rapid population growth in stable, shallow water environments. They exhibit high adaptability to various salinity and temperature conditions, ensuring their survival and spread throughout irrigation canals and flooded fields.

Nature of damage: These snails use a radula to scrape away the epidermis and mesophyll of leaves, creating small, irregular holes and pits. This feeding behavior not only destroys the photosynthetic area of the plant but also creates entry points for secondary bacterial and fungal pathogens, leading to plant decay and potential collapse of the entire vegetation bed.

• Regular maintenance and dredging of irrigation canals to remove debris and eggs.
• Water level management, specifically periodic drying of fields to eliminate snail habitats.
• Introduction of natural biological predators such as shell-crushing fish species.
• Application of molluscicides in accordance with strict environmental regulations and integrated pest management plans.