As per the Rule 13 (Conduct of Election): If a candidate set up by a recognized political party dies, then the Returning Officer shall announce the adjournment of the poll to a date to be notified later.
However, YSR Congress is just a registered party but not a recognized party. Hence, it is not going to make any difference in the case of Allagadda Assembly segment.
AP Chief Election Commissioner Bhanwal Lal made it clear that election will be held as per the schedule in Allagadda and there willn’t be any delay. As Shobha Nagireddy is a sitting MLA and YSR Congress is one of the leading political parties in the state, He wrote a letter to Election Commission of India few hours ago seeking its opinion on the issue before making an official announcement.