CANADA STOCKS-TSX ends lower on Fed worries, Argentina fears

TORONTO, Aug 1 (Reuters) - Canada's main stock index dropped for a second straight session on Friday, dragged lower by worries about the Federal Reserve's plans to raise interest rates and fears that Argentina's default might signal broader regional instability. The Toronto Stock Exchange's S&P/TSX composite index unofficially closed down 115.48 points, or 0.75 percent, at 15,215.26. Eight of the 10 main sectors on the index were in the red. (Reporting by John Tilak; Editing by Meredith M