Evaporation residue cross sections have been measured following the fusion of 16O with 204Pb, forming the compound nucleus 220Th. These are compared with existing data for the same compound nucleus formed following fusion reactions with 40Ar, 48Ca, 82Se, and 124Sn projectiles. At energies where the reduced cross sections of xn evaporation residues would be expected to be the same for all reactions, those for the heavier projectiles are typically a factor of 10 smaller than those for 16O. This inhibition is attributed to strong competition of quasifission with fusion at the low angular momenta associated with evaporation residue formation.