Wither Proliferation?

Just had a talk with an old friend, asked me craft a wand for him. Warlord influenced with Wither on kill, at which point I asked him about it and we both realised how useless it is for hit-based builds. If you have 25% chance to inflict Wither but the mobs die within a couple hits anyway, why have wither on kill anyway?

Unless there was wither proliferation, which I realise now sounds somewhat obvious? Maybe a mastery, a runegraft, maybe some unique?