Light a new torch and look for tracks. The smell of decay may be coming from another corpse and it would be good to find it, as well as whatever may be on it.
Drink the Repel Vermin potion and carefully make your way toward the smell of death and the sound of giant wasps.
Drink the potion and continue exploring onward down the path.
Don't drink the potion just yet, but move carefully off of the path toward the smell of decay and the buzzing sounds.
Some other creative option? (please comment)