CHICAGO: U.S. wheat, corn and soybean futures fell on Tuesday on concerns that overseas buyers will turn to alternative supplies to meet their import needs, traders said.
"Consistently high prices are slowly doing their job of eroding demand across the board, with Brazil in particular among a group of global players that are plenty willing to pick up the slack," Matt Zeller, director of market information at brokerage StoneX, said in a note to clients.
Wheat futures posted the biggest decline, with the benchmark Chicago Board of Trade December soft red winter wheat contract sinking to a four-week low.
Traders were monitoring talks about keeping the United Nations-backed shipping corridor open from Ukraine's Black Sea ports. The lane has allowed exports from the key global grain supplier to pick up despite the war with Russia.
"Attention on the wheat markets remains focused on the negotiations," Commerzbank said in a note, adding that a price fall after a U.N. spokesman called the talks "positive and constructive" was a "foretaste" of what might happen if a deal is concluded.
CBOT December wheat settled down 11-1/2 cents at $8.49-1/2 a bushel. The contract bottomed out at $8.32-3/4 during the session.
CBOT November soybeans were off 13-1/4 cents at $13.72 a bushel and CBOT December corn slipped 2-1/2 cents to $6.81 a bushel.
Brazil's grain exporters association Anec on Tuesday morning raised its forecast for the country's soybean and corn exports during October, a time when U.S. shippers typically dominate the market as the bulk of the Midwest crop is harvested.
A U.S. Department of Agriculture (USDA) report on Monday showed the corn harvest was 45% complete by mid-October, slightly below market forecasts but ahead of the five-year average.
The U.S. soybean harvest was 63% complete, above the five-year average of 52%.
Traders are also assessing U.S. export prospects, which have been complicated by a strong dollar and low water levels on the Mississippi river, a major route for transporting grain to U.S. Gulf export terminals. (Reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by David Goodman, Chris Reese and David Gregorio)