Donald Trump attacked Wisconsin governor Scott Walker for failing to raise taxes in order to properly fund schools and roads on Tuesday, in a startling new break from rightwing orthodoxy from the Republican frontrunner.

The comments came after Walker endorsed Trump’s rival, Texas senator, Ted Cruz, in the GOP race.

Walker became a conservative hero for his efforts to crush public sector unions and cut government spending in the Democratic-leaning state in Wisconsin, something that led to an attempted recall of the Wisconsin governor in 2012 and became a national cause célèbre. But, in a radio interview with talkshow host Michael Koolidge on Tuesday, Trump bashed Walker’s administration.

“There’s a $2.2bn deficit and the schools were going begging and everything was going begging because he didn’t want to raise taxes ’cause he was going to run for president,” said Trump. “So instead of raising taxes, he cut back on schools, he cut back on highways, he cut back on a lot of things.”

Trump also added of the Badger State in general: “Wisconsin has a lot of problems, plus there is tremendous hatred … I wouldn’t exactly say that things are running smoothly.”

Walker, who briefly was a presidential candidate and considered a top contender for the GOP nomination, dropped out of the presidential race in September with an unheeded call for Republican rivals to consolidate around an alternative to him. In the interview, Trump said of Walker’s campaign: “We sent him packing like a little boy.”

Trump’s statements come just one week before Wisconsin’s crucial primary. The state, which awards 42 delegates to the Republican National Convention, represents the best opportunity for the frontrunner’s opponents to beat him before the campaign moves to more favorable terrain for Trump in the north-east later in April.