Stable Fly

Adult Stable Fly

Stable flies are also common in cattle farms and are similar in appearance to house flies at first glance, but can easily be distinguished by their biting habits. The mouth parts of these flies are formed into a sharp proboscis which can be seen under the head pointing forward, parallel to the resting surface.

It can best be seen from the side. The fly uses this proboscis to pierce the animal's skin and suck blood. The presence of such flies is usually unmistakable - they bite not only animals but also people. Afflicted animals are seldom calm and will be quite distressed by large fly populations. The larvae of this species develop in moist vegetable matter often contaminated by animal urine and faeces and therefore will generally be found breeding outside farm buildings and often around the edges of buildings, but in various areas of pasture as well. They can be a particular problem around silage storage areas, spoiled feed grain and calf breeding boxes with straw covered floors. These flies may travel some distance from their breeding sites in search of food (blood).

Because the larval breeding habitat is often ill-defined, most control measures need to be directed against the adult flies. Only wall sprays will be effective as the biting mouth parts of these flies do not allow them to eat bait.

Cattle try to keep flies away: more than 14 ,000 defensive movements in 12 hours result in harassment of the animals, with serious consequences.

With its proboscis specially adapted as a needle the stable fly (Stomoxys calcitrans) pierces several of its hosts' blood vessels twice a day.