  Ferroquadrupole order associated with local $4f$ atomic orbitals of rare
earth ions is a realization of electronic nematic order. However, there are
relatively few examples of intermetallic materials which exhibit continuous
ferroquadrupole phase transitions, motivating the search for additional
materials that fall in to this category. Furthermore, it is not clear a priori
whether experimental approaches based on transport measurements which have been
successfully used to probe the nematic susceptibility in materials such as the
Fe-based superconductors, will be as effective in the case of $4f$
intermetallic materials, for which the important electronic degrees of freedom
are local rather than itinerant and are consequently less strongly coupled to
the charge-carrying quasiparticles near the Fermi energy. In the present work,
we demonstrate that the intermetallic compound YbRu$_2$Ge$_2$ exhibits a
tetragonal-to-orthorhombic phase transition consistent with ferroquadrupole
order of the Yb ions, and go on to show that elastoresistivity measurements can
indeed provide a clear window on the diverging nematic susceptibility in this
system. This material provides a new arena in which to study the causes and
consequences of electronic nematicity.
