Backyard compost piles can be a source of stable flies, and youreally don’t want that. Stable flies look a lot like housefliesbut have one important difference. They bite. Volume XXXINumber 1Page 12 About the size of a housefly but with dark, irregular spots onits abdomen, stable flies have biting mouthparts through whichthey suck blood. The mouthpart, or proboscis, protrudes bayonet-like in front of its head.In the South, stable flies may breed all year, but they’re mainlypests in the spring and fall. The female lives about a week andlays 100 to 400 eggs during her lifetime.The larva is a typical whitish maggot. The pupal case is chestnutbrown and about a quarter-inch long. The complete life cycle of astable fly can take 14 to 24 days from egg to adult during warmweather.Why compost?The female fly deposits eggs in spoiled or fermenting plantmatter, such as decomposing grass clippings or hay. Larvae feedon this rotting organic material, then pupate nearby. Adult fliesemerge several days later.It’s important, then, to make sure you’re composting properly.Otherwise, you could be helping supply the neighborhood withbloodsucking flies.Both male and female stable flies feed on blood, which they getby piercing a host’s skin with their syringe-like mouthparts.They stay on the animal long enough to get a blood meal and thenseek a shaded place along a fence, barn wall or feed bunk or invegetation to digest it.Fierce bitersStable flies prefer to feed on cattle. But they’ll attack horses,dogs and other animals, too. At times, stable flies can beplentiful along the coast, too, feeding on beach-goers’ ankles.On animals, they feed on the lower portions of the body,primarily the legs and lower belly. On dogs, they feed around theperiphery of the ear, leaving the margin scabbed and bleeding.The stable fly’s bite is painful, and cattle try to dislodge themby stamping their feet, switching their tails and twitching theirskin. When flies are abundant, they’ll try to avoid them bystanding in water or bunching up, each trying to get to thecenter of the group.Horses likewise kick and stamp to deter these flies. They canmake shoeing hazardous for farriers.Contact your University of Georgia Cooperative Extension countyoffice to learn more about properly maintaining your compost pileand controlling stable flies.