(a.) Causing death or disease; noxious; pernicious\.

aggravative annoying bothering bothersome contentious disturbing exasperating exasperative galling harassing importunate importune irking irksome irritating pesky pestering pestiferous pestilent pestilential plaguesome plaguey plaguing provocative provoking teasing tiresome tormenting troublesome troubling vexatious vexing wearisome worrisome worrying