Microvelia

Microvelia (Microvelia atrolineata) is a small insect belonging to the order Hemiptera and the family Veliidae. These insects are known as riffle bugs or water striders. They primarily inhabit the water surface and the surrounding vegetation in aquatic ecosystems, frequently colonizing irrigated fields, particularly rice paddies.

The primary crop damaged by this species is rice. These bugs move across the water surface and feed on the vegetative parts of young rice plants. By piercing the stems and leaves, they extract plant sap, which deprives the plant of essential nutrients and can hinder early-stage development and general crop vigor.

The biology of Microvelia atrolineata is deeply tied to the aquatic environment. Their life cycle consists of the egg stage, five nymphal instars, and the adult stage. Eggs are typically deposited on submerged plant parts. The development rate is highly dependent on ambient temperatures and water quality, with multiple generations possible during a single growing season.

The damage caused by these insects includes yellowing of leaves, stunted growth, and potential yield reduction if the infestation is severe. Although often considered a secondary pest, their ability to multiply rapidly in favorable conditions can cause noticeable stress to rice crops, making them a point of interest for integrated pest management programs.

Effective management and control strategies include:

• Water management, such as draining fields periodically to disrupt the life cycle of the aquatic nymphs.
• Removal of aquatic weeds in irrigation canals that act as host sites during the off-season.
• Application of specialized insecticides only when economic injury thresholds are reached to preserve natural predators.
• Promotion of biodiversity within the field boundaries to support natural biological control agents.