CHICAGO: US 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.” Wheat futures posted the biggest decline, with the benchmark Chicago Board of Trade December soft red winter wheat contract sinking 1.9% 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 UN spokesman called the talks “positive and constructive” was a “foretaste” of what might happen if a deal is concluded.

At 11:07 a.m. CDT (1607 GMT), CBOT December wheat was down 16-3/4 cents at $8.44-1/4 a bushel.

CBOT November soybeans were off 14-1/2 cents at $13.70-3/4 a bushel and CBOT December corn was 4-3/4 cents lower at $6.78-3/4 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 US shippers typically dominate the market as the bulk of the Midwest crop is harvested.

A US 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 US soybean harvest was 63% complete, above the five-year average of 52%.

Traders are also assessing US 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 US Gulf export terminals.