Fly baits used in trash areas are effective in reducing the number of flies around buildings if good sanitation practices are followed. When flies have access to garbage, however, they will not be controlled by baits. Always follow the directions on the insecticide label for safe application. Both Fannia canicularis and Fannia femoralis can be abundant during the cooler months in southern California and are considered major winter pest flies. Fannia at rest hold their wings more over the back than Musca, creating a narrower V-shape to the wing outline.
Females typically spend most of their time feeding and laying eggs near the larval development site.
The immature stages are adapted to tolerate a wide moisture range in the larval development substrate. Egg laying and larval development frequently occur in animal wastes, but various moist organic materials can serve as suitable substrates. Larvae of Fannia spp. Backyard compost heaps and decomposing piles of grass clippings can produce large numbers of Fannia. Their habit of hovering at face height makes them annoying, though they move readily out of the way when approached.