Phorid flies are about 1/16 to 1/8 inch long, dark brown to almost black, and move in a characteristic short, nervous, jerky manner. The largest segment of the hind leg is distinctly flattened laterally.
phorids are usually most common in late summer and early fall cropping. Tthe flies are attracted to light, and swarm near windows and doors in growing rooms and packing sheds. It is a common sight to see numbers of dead phorid flies on the floor beneath windows and near doors.
Life Cycle: Phorid female are about 3 mm in length.They lay smooth elongated ovoid eggs beneath the surface of compost or in the casing. The eggs hatch in 2 to 3 days, and newly emerged larvae are nearly transparent and taper towards the “head end. With maturity, they become whitish and are about 4.5 mm in length; end-to-end, about five and one-half larvae equal an inch. At 65˚F, the larvae cycle will be completed in about 14 days.
The pupae appears to be whitish initially, but quickly becomes dark yellowish-brown. The pupal stage requires 20 days at 65˚F. Adult flies may live for about 8 days, but the length of a generation varies considerably with temperature.
Phorid flies are native to South America where they and other predators keep red imported fire ants in check, Schofield said. The female flies attack the ants and lay eggs in their bodies. Larvae eventually hatch and burrow into the ants’ heads. There, they grow and release enzymes that cause the heads to fall off. Mature flies eventually emerge from the decapitated heads, and the cycle starts over.
Control: Eliminate breeding grounds, Sanitation, Use Fly Sprays to kill adult flies.
Sanitation: Eliminating fly breeding sites, the material to which they are attracted to and on which they lay eggs, is usually sufficient to eliminate and prevent fly infestations. Conversely, without thorough sanitation, other control methods are largely ineffective. Therefore, trash should be kept in sealed containers . Dumpsters should be kept as clean as possible, emptied regularly and kept as far away from buildings as is practical. Manure and other decaying plant and animal material should be promptly removed. Also, eliminate areas of excessive moisture.