Critical Strikes with Daggers have a 40% chance to Poison the Enemy
20% increased Damage with Poison
+15% to Damage over Time Multiplier for Poison from Critical Strikes 
Adder's Touch is a notable passive skill that grants increased damage with poison, and additional critical strike multiplier with daggers. It also grants additional chance to poison on critical strikes with daggers and additional damage over time multiplier for poisons from critical strikes.