  We report direct evidence of pre-processing of the galaxies residing in
galaxy groups falling into galaxy clusters drawn from the Local Cluster
Substructure Survey (LoCuSS). 34 groups have been identified via their X-ray
emission in the infall regions of 23 massive ($\rm \langle M_{200}\rangle =
10^{15}\,M_{\odot}$) clusters at $0.15<z<0.3$. Highly complete spectroscopic
coverage combined with 24 $\rm\mu$m imaging from Spitzer allows us to make a
consistent and robust selection of cluster and group members including star
forming galaxies down to a stellar mass limit of $\rm M_{\star} =
2\times10^{10}\,M_{\odot}$. The fraction $\rm f_{SF}$ of star forming galaxies
in infalling groups is lower and with a flatter trend with respect to
clustercentric radius when compared to the rest of the cluster galaxy
population. At $\rm R\approx1.3\,r_{200}$ the fraction of star forming galaxies
in infalling groups is half that in the cluster galaxy population. This is
direct evidence that star formation quenching is effective in galaxies already
prior to them settling in the cluster potential, and that groups are favourable
locations for this process.
