 The spelling with the ""o"" won, as it was closest to bioterrorism and thus would be easier to remember.Clemson University's Regulatory and Public Service Program listed "diseases vectored by insects" among bioterrorism scenarios considered "most likely".Because invasive species are already a problem worldwide one University of Nebraska entomologist considered it likely that the source of any sudden appearance of a new agricultural pest would be difficult, if not impossible, to determine.