U.S. corn exports jumped to the highest in at least 23 years amid adverse crop weather in the Americas and the threat of Chinese trade tariffs. A persistent drought in Argentina has cut grain output, and dry weather into May may curb production of the second-season harvest in Brazil. Cold, wet weather in the next two weeks will crimp U.S. planting, increasing risks that Midwest crops will pollinate during hot weather in July, further reducing prospects for global supplies. U.S. exports in the week ended April 5 jumped 60 percent to 1.94 million tons from a year earlier to the highest since the Department of Agriculture began reporting the data in 1995. Japan and Mexico were the biggest buyers with a small amount sold to China, which is embroiled in a trade dispute with the Trump administration.