Srivastava was given the party ticket last year and had already started his election campaign.
Local leaders had refused to promote Raju and help him expand base.
Sources said Srivastava was unhappy with the local leaders who had refused to promote him and help him expand base.
While the SP leadership, including party chief Mulayam Singh Yadav and Chief Minister Akhilesh Yadav, apparently asked him to stay but he decided to quit.
A senior leader said that the party too was waiting for the comedian to call it a day as the contest on each seat had become important.