Ballot Access News reports that for the “first time in Michigan history, a third party has a contested gubernatorial primary.” From the April 19 article by Richard Winger:

On August 7, 2018, Michigan holds primaries for the Republican, Democratic, and Libertarian Parties. The Libertarian primary ballot will list two candidates for governor, Bill Gelineau and John Tatar. Any registered voter will be able to choose to vote in the Libertarian part of the primary ballot (the ballot has all three parties on it, but voters must confine their voting to just one party’s portion).

This is the first time that any party other than the Democratic or Republican Parties has had a contested gubernatorial primary in Michigan. Michigan has been holding primaries since 1910. Although all qualified parties nominated by primary before 1931, no previous third party happened to have a contested primary for governor.

Since 1931, only minor parties that had polled an unusually high vote have been entitled to their own primary. They are American Independent Party in 1970, Anderson Coalition Party in 1982, the Tisch Independent Citizens Party in 1988 and 1992, the Reform Party in 1998, and the Libertarian Party in 2018.