Cotton farmers in Argentina, Paraguay and Brazil will lose output after a prolonged dry spell damaged some crops, according to MDA Information Systems.

“Dryness has certainly caused some notable stress and losses on the cotton crops,” which got less than half their normal rainfall, Don Keeney, a senior agricultural meteorologist at Gaithersburg, Maryland-based MDA, said in an e-mail today.

Fields across the affected areas got about 124 millimeters (4.9 inches) of rainfall from Nov. 19 to Jan. 17, compared with an average of 259 millimeters for that period in the last 30 years, Keeney said.

Recent rains in western Brazil, the worldΆs fifth-largest grower, were too late to help crops and may hurt plants because “they are in open boll,” Keeney said. “The only area that did not see significant stress this season was northwest Argentina and northwest Paraguay.”

China is the biggest producer, followed by India, the U.S. and Pakistan.

Cotton for March delivery declined 2 percent to 96.21 cents a pound by 12:54 p.m. on ICE Futures U.S. in New York. The price tumbled 37 percent last year, its biggest annual slump since 2004.