The war in Ukraine and forecasts of reduced supplies due to cold weather in the United States pushed grain prices higher.

Corn futures on the Chicago Board of Trade (CBOT) topped $8 a bushel on Monday and hit their highest price in nearly a decade on concerns that unfavorable weather in the United States and the war in Ukraine disrupted grain exports.

Traders worry that cold weather will slow planting of this spring’s U.S. crops and could reduce yields at the fall harvest. Rich Feltes, director of market insights at brokerage RJ O’Brien, said the forecast showed “only a short window of opening for Midwest planting” through the end of the month.

Planting has started slowly, and as of April 10, the planting rate was 2 percent, below the five-year average of 3 percent. USDA will release an update on farmers’ progress in a weekly report at 3 pm CDT (2000 GMT).

“It looks like some corn will be planted by the end of April, but the war in Ukraine continues,” said Dennis Smith, a commodities broker at Archer Financial Services in Chicago.

A tractor spreads fertilizer on a wheat field near the village of Yakovlevka, Ukraine [Thomas Peter/Reuters]

U.S. food production is particularly important this year as the war in Ukraine has raised doubts about its acreage and hampered agricultural exports from the Black Sea region, a major global supplier of corn and wheat.

About 1.25 million tonnes of grains and oilseeds are still stranded on merchant ships in Ukrainian seaports due to the Russian invasion, some of which could deteriorate in the near future, Ukraine’s agriculture minister said on Friday, citing Ukraine’s agriculture minister.

The CBOT’s most active corn futures, Cv1, climbed to $8.03 a bushel, the highest level since September 2012. The contract was up 18-3/4 cents at $8.02-1/2 bushel by 10:10am CDT (15:10GMT).

CBOT Soybeans Sv1 gained 24 cents to $16.89-1/4 a bushel, while CBOT Wheat Wv1 gained 28-1/2 cents to $11.33 a bushel and was near a four-week high.

Wheat futures recovered after the most active contract, Wv1, posted its biggest drop in nearly two weeks on Thursday. The CBOT market was closed on Friday.