* TSX falls 49.74 points, or 0.39 percent, to 12,789.26 * Trading volumes are sluggish * Eight of 10 main sectors decline * Suncor has biggest negative influence on market * Takeover target BlackBerry drops about 3 percent By John Tilak TORONTO, Oct 3 (Reuters) - Canada's main stock index slipped on Thursday as a U.S. government shutdown dragged into a third day, offsetting positive economic data from China and weighing on most major sectors. Investors also had an eye on BlackBerry, which is the focus of a $4.7 billion bid from a consortium led by Fairfax Financial. Shares of the smartphone maker shed nearly 3 percent. Data showed rising demand caused activity in China's services sector to expand at the fastest pace in six months in September but failed to lift sentiment. The focus of the market remained the U.S. government shutdown, which highlighted the political gridlock in Washington over the debt crisis and the uncertainty investors are facing as no immediate resolution seemed in sight. "Who knows what's going to happen or how long it's going to drag out," said Sal Masionis, stockbroker at Brant Securities. "You just stay away and do nothing, and have a little cash on the side." Investor confidence in Canada and the United States has taken a beating, he said, adding that the uncertainty could drag on until the end of the month. Volumes on the benchmark Canadian index were sluggish. About 56 million shares changed hands on Thursday at mid-morning, compared with an average daily volume of 304 million shares in September, according to market operator TMX Group. The Toronto Stock Exchange's S&P/TSX composite index was down 49.74 points, or 0.39 percent, at 12,789.26. The TSX could lose ground before the end of the year due to the U.S. debt and budget troubles, Masionis said. Eight of the 10 main sectors on the index were in the red on Thursday. Shares of energy producers fell 0.7 percent, weighing the most of any major sector. Suncor Energy Inc lost 1.1 percent to C$36.40 and had the biggest negative influence on the market. Canadian Natural Resources Ltd gave back 0.3 percent to C$32.13. The materials sector, which includes mining stocks, slipped 0.3 percent despite small gains made by gold stocks. Potash Corp was down 0.9 percent at C$33.61, and Teck Resources Ltd declined 0.8 percent to C$27.67. BlackBerry slipped to C$8.03, taking the information technology sector down 1.3 percent.