  The effect of breakup is investigated for the medium weight
$^{6}$Li+$^{59}$Co system in the vicinity of the Coulomb barrier. The strong
coupling of breakup/transfer channels to fusion is discussed within a
comparison of predictions of the Continuum Discretized Coupled-Channels model
which is also applied to $^{6}$He+$^{59}$Co a reaction induced by the borromean
halo nucleus $^{6}$He.
