New Zealand skipper Brendon McCullum has criticised Australia opener David Warner for not acknowledging England's Joe Root's fine century in the first Ashes Test.He added that Warner "may have a few regrets about the way he carries on" once his playing days are over. McCullum pointed out a moment in the Ashes first Test when Joe Root reached three figures in England's first innings, Warner failing to applaud that.England defeated Australia by 169 runs to go 1-0 up in the five-Test series."David Warner is a fine player, but I was disappointed to see some of the petulance on show in Cardiff. When Joe Root got his hundred, Warner just stood there with his arms folded. There was no applause," McCullum wrote in a column for dailymail.co.uk on Monday."Some of the great Australian players, guys like Shane Warne, Ricky Ponting, Adam Gilchrist, Mike Hussey - were hard customers on the field. But if you had success against them, they'd go out of their way to acknowledge it. I understand the way Warner's trying to play, but he needs to show more respect," he said."He might look back on his career and have a few regrets about the way he carries on. The danger is that people won't think about his cricket as much as they should," McCullum said.Warner and Root share fractious history after the former was disciplined by Cricket Australia in 2013 following a physical altercation at a nightclub.