Water boatman

Water boatmen (family Corixidae) are small aquatic bugs adapted to living in stagnant or slow-moving water bodies. Their bodies have an oval, slightly flattened shape, and adult size ranges from 5 to 15 mm.

A distinctive feature of these insects is their hind legs, which are modified into oars covered with dense hairs for efficient swimming. The head is large, closely pressed to the pronotum, and the eyes have a characteristic convex shape.

Unlike other aquatic bugs, water boatmen are active swimmers that frequently rise to the water surface to refresh their air supply, which is held under the elytra.

The coloration of adults usually varies from gray to brown with transverse dark stripes, providing them with excellent camouflage among bottom sediments and aquatic vegetation.

Systematically, water boatmen belong to the order Hemiptera, family Corixidae, which includes many species, some of which are herbivorous while others are predatory.

Water boatmen cause primary damage in rice paddies and fish farms, where they can reproduce in massive numbers if agro-technical regimes are violated.

In rice fields, these pests damage seedlings and young shoots by sucking juices from plant tissues, which leads to stunted growth and stem deformation.

Water boatmen pose a serious threat to fish fry in ponds, as massive populations create food competition and cause direct mechanical damage to larvae.

In intensive agriculture, water boatmen can act as vectors for fungal and bacterial plant diseases by damaging the plant epidermis with their mouthparts.

Economic damage also includes the contamination of water bodies with insect waste, which degrades the quality of irrigation water and the aquatic environment.

The activity of water boatmen begins in early spring when water temperatures in reservoirs reach 10-12 degrees Celsius, prompting adults to emerge from hibernation sites.

The period of intensive reproduction and egg-laying occurs in May and June, when insects migrate to warm shallow areas of rice fields or ponds.

The summer generation is characterized by high density, requiring constant monitoring of crop conditions in July, especially during dry weather.

In autumn, adults prepare for wintering by moving deeper into the bottom silt, where they remain viable at low temperatures.

The complete life cycle of one generation lasts an average of 30–45 days, depending on the temperature regime and the availability of food sources in the water.

The first sign of infestation is the presence of a large number of active individuals near the water surface, which quickly dive to the bottom when disturbed.

Leaves of young crops show small, pin-prick punctures that may eventually merge into necrotic spots surrounded by a chlorotic halo.

Visual inspection of the water reveals characteristic egg clusters, which are often attached to plant stems or debris near the shoreline.

The presence of a significant population is accompanied by a specific sound produced by males rubbing their limbs against their bodies, resembling chirping.

Damaged plants exhibit stunted growth, signs of general distress, and, in cases of heavy infestation, may die completely during the tillering stage.

Effective agro-technical control involves draining rice paddies and deep plowing the soil after harvest to destroy the pest's overwintering sites.

Regulating water levels in rice irrigation systems, including the creation of flow-through conditions, significantly reduces the probability of mass water boatman reproduction.

The use of biological control methods, such as utilizing natural predators (predatory insects, waterfowl, or entomopathogenic microorganisms), yields positive results.

In extreme cases where the economic threshold is exceeded, the use of insecticides approved for aquatic ecosystems may be necessary.

• Implementing crop rotation to break the insect life cycle.
• Removing excess vegetation from channels and ponds.
• Monitoring population levels using light traps at night.