[GAMEPLAY] Duskblade does not disable control wards.
Considering the high cooldown and the fact that camouflage champs may want to buy it:

It should be able to disable control wards. They DO pop the passive. But [ANOTHER BUG] you need to walk really fucking close to them. So it only lets you know you're seen. It doesn't disable them. And sometimes it won't even let you know you're seen, cuz you didn't walk close enough to pop it.