(Adds details on sectors and stocks, updates prices)
* TSX down 121.63 points, or 0.89 percent, to 13,579.84
* Six of the TSX's 10 main groups slip
TORONTO, May 9 (Reuters) - Canada's main stock index fell to a three-week low on Monday as lower commodity prices weighed on energy and mining stocks, while financials also fell.
The index fell 1.8 percent last week, pressured by a weakening in commodity prices and a wildfire that led to production cuts in Canada's oil sands region. It touched a six-month high of 13,972.62 on April 29.
The most influential movers on the index on Monday included Barrick Gold Corp, which fell 4.4 percent to C$22.78, and Goldcorp Inc, which declined 3.3 percent to C$23.96.
Spot gold fell 1.7 percent, while copper hit its lowest in nearly a month as weak trade data from top consumer China highlighted poor demand growth prospects and the dollar rose after a Fed official kept rate hike expectations intact.
The materials group, which includes precious and base metals miners and fertilizer companies, lost 3.5 percent.
Suncor Energy Inc, which cut production last week due to the wildfire, fell 2.5 percent to C$33.00.
Oil prices fell as caution among investors prevented a return to late April's 2016 highs. U.S. crude futures fell 2.5 percent to $43.53 a barrel, while the overall energy group was down 2.1 percent.
At 11:03 a.m. EDT (1503 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 121.63 points, or 0.89 percent, to 13,579.84. Six of the index's 10 main groups were in positive territory.
Canadian officials were hoping to take their first look at Fort McMurray, ravaged by the nation's most destructive wildfire in recent memory as firefighters hoped cooler, possibly rainy weather would help them battle the blaze.
About half of Canada's daily oil sands crude capacity was out of service on Friday and some pipelines were closed.
Financials dipped 0.3 percent, including a 0.6 percent drop in the shares of Royal Bank of Canada to C$75.62.
Valeant Pharmaceuticals International Inc said it expected to file its first-quarter report with U.S. and Canadian regulators on or before June 10, ahead of a July 31 deadline, and reiterated its first-quarter forecasts. Its shares edged up 0.3 percent to C$38.69. (Reporting by Fergal Smith; Editing by James Dalgleish)