Suspicious fire destroys mowing company

Fifty firefighters were needed to bring a roaring fire under control at a lawn-mowing business north of Adelaide.

The blaze in Willaston, which was well alight by 5am on Sunday, is being treated as suspicious.

A fire service spokeswoman says it took two hours to contain the fire, and it would take several hours to extinguish it.

"The damage bill has been set at about $500,000 and the cause is believed to be suspicious," she said.

Sergeant Andrew Pomeray said investigations were under way into the cause of the fire.

"We believe there may be some evidence of a break-in," he said.