Which word completes the analogy? Antiseptic : Germs :: Insecticide : ?

The relation is a substance : the living thing it is made to destroy. An antiseptic kills germs; an insecticide kills insects, as the word itself declares. The distractors are the targets of the neighbouring preparations a farmer keeps on the same shelf — weeds are killed by a weedicide, rodents by a rodenticide and fungus by a fungicide — so each is plausible only until the prefix is read.