Skip Ribbon Commands Skip to main content
Share This

Ectoparasites - Stomoxys

Stomoxys calcitrans: Stable fly

General Description: The flies are about as large as the domestic flies, and are characterised by the presence of a prominent proboscis. The thorax is grey and has four longitudinal dark stripes. The abdomen is short and broad and has 3 dark spots on the second and third segments.

Life Cycle: The female of Stomoxys calcitrans usually lays her eggs in decaying vegetable matter, especially if contaminated by urine. Sometimes this fly also lays her eggs in horse manure. A female is capable of laying a total of 800 eggs in batches of 25 - 50 eggs at a time. Depending on the temperature, the larvae can hatch in 2 to 4 days and mature into adult in 14 to 24 days. Oviposition begins 6 to 9 days after emergence of the female, provided a few meals of blood have been taken.

Location: The fly comes in contact with the horse only at the time of sucking blood.

Geographical Distribution: Worldwide.

Significance: Although S. calcitrans is an important nuisance, causing irritation at the area of the bite, its main importance is as a mechanical vector of several diseases although most these diseases do not occur in New Zealand. S. calcitrans has been found to be a vector of Trypanosoma evansi (agent of surra), T. equinum (agent of "mal de caderas"), T. brucei and T. vivax (agent of nagana). Equine infectious anaemia may also be transmitted by S. calcitrans. The stable fly can also serve as an intermediary host for Habronema spp worm larvae.

Control: Destruction of breeding places by regular removal of moist bedding, hay and faeces from stables and yards helps in the control of S. calcitrans. The spraying of sunny walls, where the flies prefer to rest, utilising an insecticide with residual effect is also useful in the control of stable flies.


Back to Horse Disease Information ​