Saucer bug

Systematic position
The saucer bug (Ilyocoris cimicoides) belongs to the order Hemiptera and the family Naucoridae. It is an aquatic predatory insect that thrives in freshwater habitats, such as stagnant ponds or slow-moving streams, particularly those with dense vegetation cover.

Crops affected
While the saucer bug does not feed on terrestrial crops, it is a significant pest in aquaculture. It poses a direct threat to fish hatcheries and nurseries by preying upon fish fry and fingerlings, thereby causing economic losses in agricultural water bodies.

Biology and life cycle
The life cycle consists of egg, nymphal, and adult stages, all occurring within the aquatic environment. Adults have a flattened, oval body shape and specialized raptorial front legs designed to grasp prey. They are strong flyers, allowing them to migrate between ponds and colonize new aquatic areas rapidly.

Damage and harmfulness
The harmfulness of this insect is primarily due to its aggressive predatory nature. By injecting paralyzing enzymes into small fish, the saucer bug causes significant mortality among juvenile populations. High densities of these bugs can deplete fish stocks, leading to poor growth rates and harvest losses.

Control measures
Management strategies to control saucer bug populations focus on environmental manipulation:

• Regular management and removal of excessive aquatic weeds that provide habitats for the bugs.
• Draining and drying of fish ponds between production cycles to eliminate breeding and overwintering sites.
• Using fine-mesh screens on water supply inlets to prevent the migration of adults into commercial ponds.
• Maintaining optimal stocking densities to ensure the resilience of the fish population.