PARIS/SINGAPORE- Chicago grain futures eased to one-week lows on Thursday as strength in the dollar and advancing U.S. corn and soybean harvests pushed prices away from recent highs fuelled by Chinese demand.

"A stronger U.S. dollar is not helping, but we also suspect the market is fatigued after such a strong rally from mid-August," said Tobin Gorey, director of agricultural strategy at Commonwealth Bank of Australia.

A flurry of export sales to China, together with concern over weather damage to U.S. corn and soybean crops, had fanned a rally in Chicago prices, with soybeans reaching a two-year high, corn a six-month peak and wheat a five-month top. GRA/

But the start of U.S. corn and soybean harvesting, with favourable weather expected for field work in the coming days, encouraged prices to ease.

The dollar, which hit a two-month high against a basket of currencies on Thursday, also weighed on U.S. grains, particularly U.S. wheat, which has struggled to compete overseas against Russian supplies. 

The dollar's strength was linked to worries about further economic fallout from a coronavirus epidemic that has accelerated again in Europe.

"Soybeans are reflecting the concerns that demand could suffer again from the pandemic," a European trader said.

The most-active soybean contract on the Chicago Board Of Trade (CBOT) Sv1 was down 1.2% at $10.02 a bushel by 0958 GMT, as it approached the psychological $10 chart level.

CBOT corn fell 1.49% to $3.63-1/4 a bushel and wheat Wv1 was down 1.1% at $5.43-1/4 a bushel.

All three crops struck one-week lows earlier in the session.

However, strong demand from China helped limit declines.

The U.S. Department of Agriculture (USDA) has reported soybean sales to China in each of the past 14 trading days. 

Traders are also turning their attention to South American harvest prospects.

Argentina's upcoming soybean and corn crops will be smaller than last season's due to dry weather and capital controls, the Buenos Aires Grains Exchange said. 

(Reporting by Gus Trompiz; Editing by Mark Potter) ((gus.trompiz@thomsonreuters.com; +33 1 49 49 52 18; Reuters Messaging: gus.trompiz.thomsonreuters.com@reuters.net))