The Collaborative International Dictionary of English v.0.48:

germicide \ger"mi*cide\ (j[~e]r"m[i^]*s[imac]d), n.
   A germicidal agent. -- a. Germicidal.
   [1913 Webster]

WordNet (r) 3.0 (2006):

germicide
    n 1: an agent (as heat or radiation or a chemical) that destroys
         microorganisms that might carry disease [syn:
         disinfectant, germicide, antimicrobic,
         antimicrobial]

Moby Thesaurus II by Grady Ward, 1.0:

52 Moby Thesaurus words for "germicide":
   aborticide, acaricide, anthelmintic, antibiotic, antiseptic,
   bactericide, bug bomb, carbamate insecticide, chemosterilant,
   chlorinated hydrocarbon insecticide, contact poison, defoliant,
   disinfectant, eradicant, fratricide, fumigant, fumigator,
   fungicide, genocide, herbicide, homicide, infanticide,
   insect powder, insecticide, matricide, microbicide, miticide,
   organic chlorine, organic phosphate insecticide, parricide,
   patricide, pesticide, poison, rat poison, regicide, roach paste,
   roach powder, rodenticide, sororicide, stomach poison, suicide,
   systemic, systemic insecticide, toxic, toxicant, toxin, uxoricide,
   venin, venom, vermicide, virus, weed killer