By Nivedita Bhattacharjee and Sumeet Chatterjee MUMBAI (Reuters) – Indias second largest IT services exporter Infosys Ltd is under pressure to bring in a new chief executive soon to check an exodus of junior staff and reassure investors after a slew of departures at the top. Shares in Infosys, the most widely held Indian stock, fell to their lowest level in nine months on Thursday, the day after it announced president and board member B.G. Srinivas had resigned. The departure of Srinivas, the 10th senior executive to exit in the last year, widens a leadership vacuum at Infosys as it searches for a new chief executive. Srinivas was widely seen as a frontrunner for the top job among internal candidates after Chief Executive S.D. Shibulal, one of companys seven founders, said in April that he wants to retire by January 2015 at the latest.