Harare – Zimbabwean opposition party, Zapu, has called on President Robert Mugabe to pluck a leaf from the late former Cuban leader Fidel Castro and step down.During the time of his failing health, Castro decided to retire from politics in 2008, a move that Mugabe has been urged to emulate, News Day reported on Tuesday.Castro died on Friday after a long battle with illness. He was aged 90. Zapu spokesperson, Iphithule Maphosa said that the former leader did the right thing by stepping down. "We also commend and learnt from his wise leadership after he retired when the time for his retirement came. We urge Mugabe to pluck a leaf from Castro and do the right thing and resign over old age and reports of ill health," Maphosa was quoted as saying.Mugabe turns 93 years old in February and speculation over his health and longevity is becoming more of an issue, where signs of physical weakness, mental confusion or exhaustion are scrutinised during his public appearances. The ruling Zanu-PF recently endorsed Mugabe as its candidate for the upcoming 2018 presidential elections.