English duo Bland and Donald share Nedbank Golf Challenge lead
They lie on 136, six under par at the Gary Player Country club 175 kilometres (110 miles) northwest of Johannesburg.
Bland shot a second successive 68 while Donald carded a 71 after an opening round 65 in the penultimate event of the DP World Tour season.
Malaysian Gavin Green, whose 65 was the lowest second-round score, and South African Branden Grace, who fired a 67, share second place one shot behind.
A one-time winner on the European circuit, Bland birdied four holes and did not drop a shot in a delayed second round after rain and lightning halted play on Friday.
Donald, the 2023 European Ryder Cup captain, needed a par four at the final hole to take the outright lead, but three putted.
The former world No. 1 birdied four holes and bogeyed three while seeking a first win in Europe since topping the 2012 BMW PGA Championship leaderboard.
Wayward tee shots cost first-round leader Ryan Fox from New Zealand dearly as he slumped to a 74 after starting with a 64.
The son of All Blacks legend Grant Fox had to play too many approach shots from the rough in a round that included four birdies, four bogeys and a double bogey.
Fox and Dane Rasmus Hojgaard, who produced a second straight 69, trail Bland and Donald by two strokes.
The third round will also be played on Saturday.
