The Ykesha will proc at level 1 for full 50 HPS damage. However the "recommended 57" will drastically weaken the weapon into which it's inserted. For example as a test I made a warrior and equipped him with a Kreizenn's Flame, which is a 12/17 1HS weapon with 50 HPs, +10 STA and +20 SVFIRE. With the augment equipped it reads as 1/17, 2 HPs, 1 STA, 1 SVFIRE. It also has its own 100pt Flame of the Efreeti damage proc. Both procs go off. Since proc rate is tied to dexterity, I'm sure it will proc more often as a noobie toon levels up and raises his DEX.
Since the augment cripples the weapon into which it's inserted, until you hit the recommended level of 57, best to put it into a low-damage but very fast weapon. Would be interesting to see it inserted into a Mosscovered Twig 'cept that old school weapon has no augment slots.