ST. PAUL — Candidates running for Minnesota governor are taking their pitch to primary voters to the airwaves, as Democratic state Rep. Erin Murphy launched the latest statewide TV ad Friday in the wide-open race to replace outgoing Gov. Mark Dayton.

It’s the start of what’s sure to be an onslaught of political advertising in Minnesota this election season as Republicans and Democrats race toward an Aug. 14 primary that will settle the names on the ballot in November. And while the open governor’s seat gets top bidding, two U.S. Senate races, an open attorney general seat and four or more competitive congressional races are also up for grabs. Campaigns and outside political groups have already reserved millions of dollars in ad space for the fall.

Murphy was the last among the three Democrats running for their party’s nomination to release a statewide ad, which her campaign said was a “six-figure” reservation that will run until Aug. 14. But Murphy’s ad doesn’t mention fellow Democrats U.S. Tim Walz or Attorney General Lori Swanson. Instead, it takes a shot at GOP candidate and former Gov. Tim Pawlenty while touting her own accomplishment while serving as House majority leader in 2013 and 2014.

“I went to the mat on the minimum wage and marriage equality, and we delivered,” the longtime lawmaker says to the camera while walking with a crowd of supporters.

Walz and Swanson have been broadcasting hundreds of thousands of dollars of ads for more than a week, with Walz focusing on critiquing President Donald Trump and his background as a high school teacher and Swanson promoting her three terms as attorney general.

Meanwhile, Republican Hennepin County Commissioner Jeff Johnson released the first of several promised statewide radio ads Friday. It’s his first substantial counter to weeks of the better-funded Pawlenty’s broadsides against him in a statewide TV attack ad that said Johnson supported higher property taxes and Dayton’s since-abandoned plan to broaden the Minnesota sales tax. Johnson called those ads false and called on Pawlenty to pull them off air.

Johnson’s radio ad calls Pawlenty “an establishment, poll-driven Republican” and repeats the former governor’s comments from October 2016 that then-candidate Trump was “unhinged and unfit” to be president. The details on the scope of Johnson’s radio ad buy were not immediately available.