Wheat surged the most in six months on concern that frost is hurting winter crops in the Great Plains and wet, cold weather will delay spring planting in North America. Corn also rose, while soybeans fell.

Freezing temperatures last week may have damaged the grain in the southern Great Plains, Bryce Anderson, an agricultural meteorologist at DTN, wrote Tuesday. The government said this week that U.S. winter-wheat crops have improved little since November, when they were in the worst condition since government record-keeping began in 1985. Snow depths with the equivalent of as much as 7 inches of moisture may delay spring planting from Minnesota to Canada this year, T-Storm Weather said in a report Wednesday.

“The wheat crop in Oklahoma and northern Texas got hurt by the cold temperatures last week,” Roy Huckabay, an executive vice president for the Linn Group in Chicago said in a telephone interview. “Crop development in that area was far enough along that yields will be lower.”

Wheat futures for delivery in May jumped 3.8 percent to close at $6.965 a bushel on the Chicago Board of Trade, the largest gain since Sept. 28. Prices still are in a bear market, down 26 percent from last year’s closing high and touched a nine-month low of $6.5975 on April 1.

About 34 percent of the U.S. winter-wheat crop was rated good to excellent in the first rating of the season, the lowest for the date since 2001 and up from 33 percent in November, according to the latest U.S. Department of Agriculture data released April 1.

Overseas demand

Milling wheat futures traded in Paris for delivery in May added 1.6 percent to 240.5 euros ($308.94) a metric ton. Winter-grain development in northern France, Europe’s largest wheat grower, is about two weeks behind normal after late autumn planting and cold spring weather, according to the European Union’s crop-monitoring unit.

“The cold, wet weather across the Northern Hemisphere is a concern and providing some support for the market,” Shawn McCambridge, senior grain analyst for Jefferies Bache LLC in Chicago, said in a telephone interview. “After the drop to multimonth lows, this week we probably have generated some overseas demand for U.S. wheat exports.”

Corn futures for delivery in May rose 0.2 percent to close at $6.415 a bushel in Chicago. The most-active contract touched $6.34 Tuesday, the lowest since June 29, after data from the USDA last week showed reserves on March 1 were above expectations and farmers plan to sow the most acres since 1936.

Soybean futures for delivery in May dropped 1 percent to $13.8025 a bushel in Chicago, after falling to $13.755, the lowest since Jan. 11.