Crippling String does nothing on Illusion of Haste, so I'm a bit skeptical here.
Tested them both.
Barbed mod increases duration of bleeding afflicted to you when using Sig of Agony (I called it the wrong name), and again when you transfer it with plauge touch/sending.
Poisonous/Crippling/Barbed Mods increase the durations of the conditions caused by traps.
There's not really any way to post a screen shot... but it's easy enough to test if you don't believe me.
The question is... does it take into account the mod when you set the trap of when its activated. So could you plant a Vipers Nest holding a poisonous bow, switch to a barbed bow and drop a Barbed Trap and get the same 33% effect on both.