  We have searched a sample of 151 young, energetic pulsars for periodic
variation in pulse time-of-arrival arising from the influence of planetary
companions. We are sensitive to objects with masses two orders of magnitude
lower than those detectable with optical transit timing, but we find no
compelling evidence for pulsar planets. For the older pulsars most likely to
host planets, we can rule out Mercury analogues in one third of our sample and
planets with masses $>0.4 M_{\oplus}$ and periods $P_b<1$ yr in all but 5% of
such systems. If pulsar planets form primarily from supernova fallback disks,
these limits imply that such disks do not form, are confined to $<0.1$ AU
radii, are disrupted, or form planets more slowly ($>2$ Myr) than their
protoplanetary counterparts.
