Trump on Thursday dismissed criticism over comments he made that appeared to take aim at Fiorina’s appearance, saying that he was only commenting on her “persona” and not her physical attractiveness. He also knocked Carson's characteristically calm demeanor and played down his medical accomplishments, saying he was only an “okay doctor.”
Trump has spent weeks targeting Bush, labeling him a "low-energy" contender whose family ties should discredit his campaign.
Asked about Trump's new targets on Thursday, Bush said: "They have to get in line."
"I think I’m still the number one beneficiary of The Donald’s insults," he said after a campaign event here on Thursday afternoon. "But look, he is who he is. He likes to disparage people. Ultimately, look, as the front runner, what’s his tax proposal? The last time he had one he called for the largest tax increase in world history. A tax on assets of 14.5 percent. He has to defend his record and he has to propose things and he has to be serious about it. If he wants to be serious candidate, he needs to act like one."
Bush spoke to a few dozen workers at R.E. Prescott Co., an equipment manufacturer, about details of his tax reform plan unveiled on Wednesday.
Earlier Thursday, Bush took to Twitter to more strongly denounce Trump's comments, calling them "small and inappropriate."
In a taped interview with CNN's Jake Tapper that aired shortly after he spoke with reporters here, Bush made similar remarks.
"Look, I don't get it. I don't see how over the long haul that you can insult your way to the nomination or the president -- certainly not the presidency -- and not the nomination either," he said.
"This disparaging of women is deeply troubling. It just doesn't make any sense to me," he added. "Carly Fiorina has made a good contribution already and will continue to make a contribution in this nomination process. She should be respected as a talented person and a viable candidate."
In New Hampshire, reporters also asked Bush whether he's preparing any differently for next week's GOP presidential debate.
"No, I’m just going to be my boring normal self," when a reporter asked him, before adding: "I am who I am.
But he reminded the pack of reporters that as Florida governor, his state police detail nicknamed him "Ever Ready."
"I’m still ever ready. I’ll be ready for the debate and more importantly, I have the energy to serve and it’s not about me," he said. "It’s not about him. It’s about the fact that people need to be lifted up right now in America and I have the energy to be on their side for sure."