Flies out as days warm: stable fly

Stable flies on the lower leg of a horse.
Stable flies on the lower leg of a horse.

THE Department of Agriculture and Food is reminding people to act now to prevent a build-up of stable fly in summer.

Senior research officer David Cook said stable fly numbers increased dramatically as the weather warmed.

“Stable fly breed in any rotting or decaying vegetable matter where there is considerable bacterial activity,” he said.

“Common breeding sites include ageing manure mixed with organic material such as straw, rotting vegetables, straw bedding contaminated by urine and faeces, rotting hay, straw or sawdust, fermenting feed and piles of grass clippings.

“Cattle and horses are most affected by the pest,” Dr Cook said.

Stable fly can cause weight loss, allergic reactions and potential heat stroke in livestock but there are ways to minimise the flies’ impact.

“After harvesting vegetable crops, make sure all reticulation is turned off and high-speed mulch all remaining vegetable crop residue,” he said.

“Apply an insecticide to the mulched residue and leave undisturbed for a week prior to incorporation into the soil.

“Also make sure any surplus vegetable produce is collected weekly, sprayed with an insecticide prior to covering with at least half a metre of soil.”

He said if stable fly larvae were found in hay residue, spray with pesticide and leave as with vegetable material.

The Department said biological and cultural treatments or stable fly traps could also be used. For more information, visit www.agric.wa.gov.au.