Shore Fly

Dalotia coriaria rove beetles hunt shore fly larvae in algae on wet floors and inside propagation trays -- they are small, fast, and worth buying for chronic greenhouses. Hypoaspis miles and similar soil mites feed on larvae and pupae in the top layer of wet media. Nematodes that target fungus gnat larvae sometimes help shore fly if you apply to saturated plugs and keep humidity high. These tools fail if you keep pressure-washing the predators away daily; biocontrol needs a stable habitat.

Shore flies breed in thin films of algae and bacteria on constantly wet mats, buckets, and hose tracks -- dry the problem before you buy anything else. Sterilize reused trays with labeled cleaners, not just a quick rinse. Fix drips and level benches so water does not pool under pots. Keep hose ends off the floor and coil them on hooks. When starting a new house, inspect incoming plugs for adult flies before you unload a truck into a clean room.

Let bench tops surface-dry between irrigations; capillary mats that are always wet are fly factories. Improve drainage so saucers and channels do not hold soup. Pressure-wash algae off walkways monthly during warm months; algae is food and nursery for larvae. Avoid bottom heat that keeps root zones steaming without moving air -- combine heat with gentle fan movement so leaves dry. In propagation, avoid over-fertilizing algae with slow leaks from fertilizer injectors into puddles.

Yellow sticky cards placed just above the crop canopy catch adults flying in the first inches of air -- use them to count trends, not as total control. In enclosed houses, a shop vac with a crevice tool removes adults from walls and glass during peak emergence before they lay eggs. Squeegee standing water off floors after every watering shift. For small grows, hand-wipe algae lines along bench edges where larvae actually live.

Insecticidal soap or neem directed into flying adults is a weak backup; adults die fast but new ones hatch from algae you did not dry. Bacillus thuringiensis israelensis drenches target larvae in water where labels allow; they are not for random dry foliage. Apply BTI to standing reservoirs, algae gutters, or recirculating mats per label -- not as a perfume on leaves. Rotate with drying and predators so you do not select soap-tolerant flies while drowning in algae.