After Iowa Republican Sen. Charles E. Grassley on Friday pulled out of an upcoming debate, his Democratic challenger Patty Judge called him out on Monday for running an insubstantial campaign. 

Judge, the Hawkeye State’s former lieutenant governor and agriculture secretary, told The Des Moines Register’s editorial board that Grassley is campaigning on trivial matters rather than his plans in the Senate.  

“He has not articulated one thing that he wants to do in the next six years,” Judge said. “This whole campaign season has been about Dairy Queens and sitting on wind turbines. There’s no substance.”

The Dairy Queen and wind turbine references allude to campaign ads showing Grassley outside an ice cream shop and on top of a windmill turbine. 

The Grassley campaign responded to Judge’s claims by highlighting key legislation, such as bills related to opioid abuse and 9/11 victims, that the six-term senator has been a part of.  

“This charge is just unbelievable coming from Patty Judge,” Grassley campaign manager Robert Haus told the newspaper. “Even in your editorial board meeting today she couldn’t think of a single piece of legislation she would work on with Sen. (Joni) Ernst.”

[Roll Call’s 2016 Election Guide: Senate]

As for the debate, it was scheduled for Oct. 20 at Iowa Public Television’s studio in Johnston, but there was a disagreement with the format IPTV provided that ultimately led to Grassley pulling out, Haus said.

“IPTV dealt with us in good faith, and we with them in good faith,” he said. “But there was an issue we couldn’t resolve.” 

He did not elaborate on what the issue was.

On Monday, an IPTV spokeswoman told the newspaper that the Grassley campaign had concerns about the presence of a studio audience, but did not say if that was the reason Grassley pulled out. 

There is one planned debate between Grassley and Judge, scheduled for Oct. 19 in Sioux City that will air on NBC stations, the same night as the third presidential debate, but the Senate debate will air earlier.  

The candidates are also currently discussing the possibility of a debate hosted by the Des Moines-based WHO Radio on Nov. 4. Grassley has said he will participate, while Judge has said she only will if the debate is broadcast by a TV station, the Register reported.  

Grassley leads by over 13 points in the latest RealClearPolitics average of polls taken between Aug. 17 and Sept. 22. The race is rated Safe Republican by The Rothenberg & Gonzales Political Report/Roll Call.