When workers at Colombia's largest flower grower organized themselves into a union...they won protections against overly long hours, potentially dangerous exposure to pesticides, and other abuses. But…the effort also may have cost the employees at the grower, Dole Food Co.'s flower division, their jobs. Last week, Estela Yepes…was handed a...letter...[saying that]...the company was closing two of its 13 farms [including Splendor-Corzo flower farm] and laying off one-third of its workforce in Colombia...Yepes and her coworkers say their farm was singled out for closure because of their success in organizing the industry's first independent union, Untraflores. Among the union's achievements: the termination of an incentive-pay plan that...was manipulated...[to]...deny workers...overtime pay...John Amaya, president of Dole's flower division, acknowledged that labor relations at Splendor-Corzo were "conflictive." But Amaya...said...that the decision to close the farm...was made on bottom-line considerations.