DETROIT--The United Automobile Workers (CIO) today set May 15 for a strike against 61 plants of the General Motors Corporation, which has defense orders totalling $750,000,000, unless an agreement upon demands for wage increases and a un ion shop is reached by that time.

The deadline was set by a conference of union executives and plant chairmen after hearing a report from their negotiation committee on nine days of conferences in Washington with company officials and a panel of the defense mediation board.

Walter P. Reuther, director of the union's G-M department, said the strike call would not affect workers among the plant's 160,000 employees who are actively engaged on the company's contracts for airplane engines, trucks, aircraft sub-assemblies, Diesel engines, machine guns, shells, and other defense work.

President Charles E. Wilson of G-M insists that the company's operations are as integrated that it is impossible to segregate the defense and non-defense workers