Poison the Troll foodstuff at the camps in Zeb'Nowa and then return to Apothecary Venustus at the Farstrider Enclave in the Ghostlands.
I'm on loan to the Farstriders in an attempt to help with their troll difficulties. I believe that I have a solution to their problem.
At my disposal are a number of potent poisons. The trolls, as you know, are living creatures and therefore must eat. If we combine my poison with their food... well, I'm sure that the results will be entertaining!
Care to help rid us of the Shadowpine trolls at Zeb'Nowa to the south? The camp straddles both the north and south sides of the road to Zul'Aman.