June 30 (Bloomberg) -- Wheat prices tumbled to the lowest in six months after a U.S. government report showed seeding of spring varieties in the northern Great Plains exceeded estimates by traders.

About 13.77 million acres were seeded with spring wheat, the U.S. Department of Agriculture said in a report today. That topped the 13 million projected by analysts surveyed by Bloomberg News last week. Inventories of all varieties on June 1 more than doubled to 667 million bushels from a year earlier, the agency said. The U.S. is the world’s largest wheat exporter.

“It’s a bearish report,” said Jason Britt, the president of Central States Commodities Inc. in Kansas City, Missouri. “We weren’t in a tight-stocks situation to begin with. If you look at the stocks numbers compared to where we stood, we had quite a bit of supply to begin with.”

Wheat futures for July delivery fell 17.25 cents, or 3.3 percent, to $5.1125 a bushel on the Chicago Board of Trade. The price earlier touched $4.9575 a bushel, the lowest since Dec. 12. The contract fell 20 percent this month as dry weather followed rain, boosting crop prospects.

Corn futures plunged the most allowed by the CBOT, dragging wheat lower. The USDA said growers will plant 87 million acres with corn, topping the estimate of 85.16 million by analysts.

“Wheat has been a follower anyway,” Britt said. “If it’s not getting help from the outside markets, wheat by default is going lower.”

Wheat is the fourth-biggest U.S. crop, valued at $16.6 billion in 2008, behind corn, soybeans and hay, government data show.

To contact the reporter on this story: Tony C. Dreibus in Chicago at Tdreibus@bloomberg.net.

Last Updated: June 30, 2009 16:07 EDT