GRAINS-Soybeans fall 1.2 pct on U.S.-China trade war, wheat at 1-week low

* Soybean lose ground as U.S.-China trade war escalates

* Wheat down for 3rd session to weakest since July 3 (Adds details, quotes)

SINGAPORE, July 11 (Reuters) - Chicago soybean futures slid 1.2 pct on Wednesday as a trade war between Washington and Beijing is curbing demand for U.S. supplies of the oilseed in top importer China.

Wheat dropped for a third consecutive session to a one-week low as improved condition of the U.S. spring crop boosted expectations of a bumper harvest.

The most-active soybean contract on the Chicago Board of Trade was down 1.2 percent at $8.61-1/2 a bushel by 0219 GMT, having closed little changed in the previous session.

Wheat dropped 0.9 to $4.87-3/4 a bushel, near their session-low of $4.86-1/4 a bushel, the lowest since July 3. Wheat closed down 3.2 percent on Tuesday.

Corn lost 0.8 percent at $3.57-3/4 a bushel, after ending the last session down 1.7 percent.

"We have a bearish sentiment in the agricultural markets as it looks like the trade war is escalating and this is hitting U.S. soybean exports to China," said Phin Ziebell, an agribusiness economist with National Australia Bank.

"U.S. weather looks good for corn as well as soybeans."

The Trump administration raised the stakes in its trade war with China on Tuesday, saying it would slap 10 percent tariffs on an extra $200 billion worth of Chinese imports.

The U.S. Department of Agriculture lowered its crop condition ratings for corn and soybeans only slightly in the latest week. Ratings for both crops remain near historical highs. 1/8nEMNI740T7

Cooler, wetter weather is expected in the six-to-10-day outlook. Much of the Midwest corn crop will be pollinating in the coming weeks, a period when stressful weather can limit yield potential.

The wheat market is being pressured by improved crop condition for the U.S. spring crop.

Spring wheat ratings in the USDA's weekly crop conditions report were above trade estimates, fuelling expectations that the agency may boost its U.S. wheat production forecast in a monthly report later this week.

Commodity funds were net sellers of CBOT corn, wheat and soybean futures contracts on Tuesday and net buyers of soymeal and soyoil, traders said. (Reporting by Naveen Thukral; Editing by Amrutha Gayathri)