Before the animated episode was the comic book. The Smurfs went black, not purple. (Not very PC, but it is nothing compared to the "Smurfette" book.) The beetle was a fly in the comic. They found that the cure was pollen from a certain flower, but the fake blue Smurf infiltrated the village and infected everyone anyway. But, when all hope seemed lost, an explosion in Papa Smurf's lab spread pollen all over the village and cured everyone.
The (older) comic books were never "sickeningly sweet". In one story one Smurf declares himself dictator in Papa Smurf's absense, in another the Smurfs almost go to civil war over a disagreement about the grammatics of their language.