TORONTO (Bloomberg) — Canadian stocks fell for a third straight day on concern that demand for the country’s resources may weaken after a report on US service industries suggested the economy is cooling.Materials and energy companies including Teck Cominco and Suncor Energy declined on falling prices for metals and crude oil, as stocks worldwide extended a slump triggered last week by the biggest drop in Chinese equities in a decade.

“The real problem is the China growth scare,” said Gavin Graham, chief investment officer at Guardian Group of Funds in Toronto, which manages about $5.1 billion in assets. “Until it’s clear that it’s just a stock market event, Canada will suffer along with the US. Any signs of weakness in the US economic data will add fuel to the fire.”

The Standard & Poor’s/TSX Composite Index slid 152.02, or 1.2 percent, to 12,711.25 in Toronto. The benchmark has fallen 5.2 percent since reaching a record one week ago.

Materials and energy stocks account for more than two fifths of the S&P/TSX. They dropped 2.6 percent and 1.1 percent, today. Commodities such as metals and energy make up more than half of Canada’s exports, of which the US takes more than 80 percent. Raw-material shares returned 38 percent as a group last year, pacing a four-year rally in Canadian stocks that lifted the S&P/TSX to its all-time closing high of 13,404.46 on February 26.

Nickel and oil led commodities lower today on concern slowing global economic growth will curb demand for raw materials. Nickel fell as much as 5.1 percent, the most in almost two months, and oil declined 2.6 percent. Gold slipped 0.8 percent in New York, erasing this year’s gains. Demand from China, the fastest-growing major economy, helped commodities climb to records in May.

Last week’s global stocks rout, which wiped out $1.8 trillion in world market value, was kicked off as the Shanghai and Shenzhen 300 Index in China, the world’s fourth-largest economy, tumbled 9.2 percent on February 27 amid concern that the government is tightening controls on investment.

China’s Premier Wen Jiabao said today that the nation is seeking slower economic growth of eight percent this year.