* Wholesale trade +0.5 pct, volume +0.3 pct
* Analysts expected +0.3 pct rise in trade
* Excluding auto sector, sales fell 0.1 pct
* Fall in farm supplies nearly offsets gain in autos
OTTAWA, Oct 21 (Reuters) - Stronger auto sales helped drive Canada's wholesale trade up by a slightly better-than-expected 0.5 percent in August, the fourth increase in five months, according to Statistics Canada data released on Monday.
The median forecast in a Reuters survey of economists was for a 0.3 percent rise, which actually turned out to be the rate at which the inflation-adjusted volume of wholesale trade rose. The volume of trade is the relevant indicator for calculating real gross domestic product.
Five of seven sub-sectors rose. Sales of motor vehicles rose 4.5 percent, the largest gain since July 2011. Excluding the motor vehicle and parts industry, wholesale sales were down 0.1 percent.
The biggest drop in dollar terms was a 12.9 percent fall in agricultural supplies, the third consecutive decline, fueled by uncertainty about global fertilizer prices, the federal agency said.
The C$231 million ($224 million) fall in agricultural supplies came close to offsetting the C$281 million increase in auto sales.