Shore fly
breed in algae growing on soil, pots, benches, and other surfaces and the female disperses her tiny (0.1 mm) eggs on the surface of the plant growing medium [...] emerge from the eggs 2–3 days later. These maggots live in and just beneath the algal crust growing on top of the soil/medium, where they feed on algae, bacteria [...] environments. In greenhouses, adults feed on algae and their larvae on algae and decaying organic matter on planting substrate. Growers consider shore