(Bloomberg) -- The US corn crop deteriorated by the most in almost three years as a lack of rain hit yield potentials in the world’s top producer of the grain. 

Just 64% of the nation’s corn crop was rated good-to-excellent in the US Department of Agriculture’s weekly report, a 5 percentage-point decline that was the biggest since August 2020 and more than double the drop forecast in a Bloomberg survey of analysts. 

The drop comes after weeks of parched weather across the Midwest that stressed young plants just as the sowing season concluded. 

“Soil moisture levels decreased sharply,” the USDA’s Indiana field office wrote in a report. Corn futures may rally in the wake of the data. Prices for the yellow grain slumped about 2% earlier Monday, in part on forecasts for rain in coming days.

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