The Collaborative International Dictionary of English v.0.48:

disseminative \dis*sem"i*na*tive\, a.
   Tending to disseminate, or to become disseminated.
   [1913 Webster]

         The effect of heresy is, like the plague, infectious
         and disseminative.                       --Jer. Taylor.
   [1913 Webster]

WordNet (r) 3.0 (2006):

disseminative
    adj 1: spreading by diffusion [syn: diffusing(a), diffusive,
           dispersive, disseminative]