US corn futures fell for a second straight session on Tuesday on demand worries as coronavirus restrictions limit travel and ethanol fuel use, and as weak livestock prices stoke fears of herd contraction, traders said.

Chicago Board of Trade May corn ended down 5-1/2 cents at $3.26 per bushel. The most-active corn contract is hovering just above a 3-1/2-year low after falling to within 1/4 cent of its contract low.

Corn prices have been hammered by weakening demand from ethanol makers, users of more than a third of the crop. Ethanol companies have curtailed production or shuttered plants due to plunging energy prices and reduced fuel demand as coronavirus-related restrictions have halted travel for many.

Shuttered US meat packing plants due to coronavirus infections have also stoked concern that cattle and hogs may be culled, cutting demand for feed grains like corn. The National Pork Producers Council on Tuesday warned that farmers facing economic losses would consider culling pigs without significant government aid.

Further weighing on corn prices, improving crop weather in southern Brazil has boosted the country's large second crop. Meanwhile, forecasts for largely dry weather in the central United States were seen boosting corn planting.

The US Department of Agriculture (USDA) said 3% of the US corn crop was planted as of Sunday, in line with trade expectations.