Martha McCord, 87

    AVOCA -- Martha E. McCord, 87, Avoca, died Friday, March 25 at the Avoca Nursing Home in Avoca.    A graveside memorial service will be held at a later date.    Survivors include her children Marion McCord of Urbandale, Melinda McCord of Omaha, NE, and Melanie McCord.    Pauley Jones Funeral Home in Avoca is in charge of arrangements.