A major search is underway for a four-year-old boy missing in outback South Australia. August, who is also known as Gus, disappeared from his remote homestead about 40km south of Yunta, in the state’s mid north, about 5pm on Saturday. Know the news with the 7NEWS app: Download todayAugust, who is also known as Gus, disappeared from his remote homestead about 40km south of Yunta. Credit: 7NEWSAn “extensive ground search” was completed on Sunday, police said, with the assistance of SES volunteers. Trail bikes, ATVs and a drone covered a 2.5km radius search area from where Gus was last seen but efforts to find the boy were again unsuccessful.