Tl;dr can dragons suffer exhaustion.

Came up with a plan to take on a big bad dragon but don't know if it will work. The campaign has these scorpion men things that have a poison that has no save, but they add 1 level of exhaustion with each hit. In the past we have been able to harvest the poison and use it in the same way, no save and one level of exhaustion with each poisoned attack that hit.

So at level 9 we have been tasked with killing an ancient blue dragon. I know dragons have all kinds of saves and such but this poison doesn't care so legendary resist wouldn't help it any. The thing I can't find is if dragons are susceptible to exhaustion. The rules just say if a creature (pretty generic) suffers 6 levels of exhaustion then they die. Figured out the best way to implement the attack for maximum firepower and hits, just not sure if the exhaustion will work for the dragon.

Any ideas?