A court has been told a market garden worker killed at Waterloo Corner in Adelaide was viciously bashed to death during a robbery attempt.

The Adelaide Youth Court heard Tuyet Van Do, 65, was killed outside his caravan at a market garden last November.

Isaac Michael Langenberg, 20, and a teenager have been charged with murder.

A second youth arrested last month has applied for bail in the Youth Court.

Prosecutors opposed the application, telling the court the victim allegedly was punched, kicked and bashed with a replica pistol and a shovel.

The court was told Mr Do was targeted because the accused thought illegal immigrants were working in the area and would keep a lot of cash on them.

The bail bid was refused and the case will return to the Youth Court next month.