  Complete fusion excitations for 11,10B+159Tb have been measured at energies
around the respective Coulomb barriers, and the existing complete fusion
measurements for 7Li+159Tb have been extended to higher energies. The
measurements show significant reduction of complete fusion cross sections at
above-barrier energies for both the reactions, 10B+159Tb and 7Li+159Tb, when
compared to those for 11B+159Tb. The comparison shows that the extent of
suppression of complete fusion cross sections is correlated with the
<alpha>-separation energies of the projectiles. Also, the two reactions,
10B+159Tb and 7Li+159Tb were found to produce incomplete fusion products at
energies near the respective Coulomb barriers, with the <alpha>- particle
emitting channel being the favoured incomplete fusion process in both the
cases.
