GRAND FORKS, N.D. — Local union officials representing the 1,300 locked out American Crystal Sugar workers have mailed letters seeking to meet with growers of the sugar beet cooperative as the harvest begins.

The union workers have been locked out of five sugar processing plants in Minnesota, North Dakota and Iowa in the company’s first labor impasse in 30 years.

Union spokesman Mark Froemke said that union officials want to talk with farmers and put their differences aside.

But company officials said they are displeased that the union is contacting growers.

Brian Ingulsrud, the company’s vice president for administration, said that would be about the same as the company trying to negotiate directly with union members. He says that would be prohibited.