Salem

Yea, I heard the same thing. I think it was rye bread? I'm not a hundred percent positive.

It was the rye bread, it got infected with ergot (which has hallucinations as one of the main symptoms) and they got ergot poisoning.

Taken from the Wikipedia article- The cause of the symptoms of those who claimed affliction continues to be a subject of interest. Various medical and psychological explanations for the observed symptoms have been explored by researchers, including psychological hysteria in response to Indian attacks, convulsive ergotism caused by eating rye bread made from grain infected by the fungus Claviceps purpurea (a natural substance from which LSD is derived), an epidemic of bird-borne encephalitis lethargica, and sleep paralysis to explain the nocturnal attacks alleged by some of the accusers. There are modern historians who are less inclined to focus on biological explanations, preferring instead to explore motivations such as jealousy, spite, and a need for attention to explain the behavior

What if the witches had just spread a plague of ergot over their crops?