Jedi were hunting for terentateks for two reasons:
1) they were outcome of Exar Kun's experiments with sith alchemy, and since Jedi hated Exar and considered all his work as pure evil, they naturally assumed that all his creations should be wiped out including poor teretateks (their grudge is easily understood - this guy almost wiped out Jedi Order)
2) Terentateks were designed to one goal: eliminating Jedi. Exar hided thousands of these creatures on various planets, and they were living jedi-traps. Since many
knights were killed by them, jedi HQ decided to wipe them out, so Jedi wouldn't be bothered on their picnics any more.