UPDATE 1-Workers threaten to paralyze Argentine grains hub over pay
May 21, 2015 at 19:20 PM EDT
BUENOS AIRES, May 21 (Reuters) - Argentina's largest labor union group will go on strike in the pivotal Rosario grains hub from June 1 if a salary dispute is not resolved, a union leader said on Thursday, threatening to bring milling and exports from the grains powerhouse to a halt.