  The recent discovery of a diffuse neutrino flux up to PeV energies raises the
question of which populations of astrophysical sources contribute to this
diffuse signal. One extragalactic candidate source population to produce
high-energy neutrinos are Blazars. We present results from a likelihood
analysis searching for cumulative neutrino emission from Blazar populations
selected with the 2nd Fermi-LAT AGN catalog (2LAC) using an IceCube data set
that has been optimized for the detection of individual sources. In contrast to
previous searches with IceCube, the investigated populations contain up to
hundreds of sources, the biggest one being the entire Blazar sample measured by
the Fermi-LAT. No significant neutrino signal was found from any of these
populations. Some implications of this non-observation for the origin of the
observed PeV diffuse signal will be discussed.
