Crawling water beetles

Affected plants: The primary diet of Haliplidae larvae consists of algae, particularly Characeae and various filamentous species. However, in artificial water bodies or nurseries, they may feed on the epidermis and soft tissues of young aquatic plants such as Nymphaea and Nuphar species. This grazing behavior can become problematic when plant density is high and food competition increases.

Biology and life cycle: Haliplidae undergo complete metamorphosis. The life cycle involves eggs, larvae, pupae, and adults. Larvae are uniquely adapted to feed by piercing algal cells and sucking out their contents. A critical stage occurs during pupation, which typically takes place in the damp soil near the water's edge, making their population dependent on stable shoreline conditions.

Nature of damage and harmfulness: The damage is manifested by the destruction of leaf epidermis and the weakening of stems. By damaging plant tissues, these beetles facilitate the entry of pathogens, leading to secondary infections and stunted growth. In ornamental nurseries, this reduces the market value and health of the stock, requiring active intervention to maintain plant aesthetic quality.

Control measures: Managing Haliplidae requires ecological and cultural strategies.

• Regular maintenance and harvesting of excess filamentous algae to reduce natural food sources.
• Manipulation of water levels during the pupation period to disturb larvae emerging for pupation.
• Encouraging natural predators such as dragonfly nymphs and carnivorous fish species.
• Physical exclusion or manual removal if localized outbreaks occur in sensitive aquatic cultures.