R. Gordon Wasson writes on his “Soma: Divine Mushroom of Immortality” pages 71-73 about the fondness Manichaeans had to mushrooms, red ones, and hence, Amanita Muscaria aka Soma, he suggests. Wasson credits St. Augustine, citing his “On the Morals of the Manichaeans”, when he condemns those who eat mushrooms. The original word in Augustine’s is “boletus”, Wasson argues that “In imperial Rome boletus was the name applied to what we call the genus Amanita, including both the edible and the toxic amanitas”. He also credits 11th century Chinese official Lu Yu as writing the Manichaeans “What they eat is always the red mushrooms” and “consider urine as a ritual water”.
The identity between the two mushrooms is questionable, he refers his own book “Mushrooms, Russia and history”. His logical conclusion is through the mention of urine and red mushrooms, that the Manichaeans used A. muscaria. Note that porcini mushrooms aka King Bolete (which were very popular in Roman cuisine) are growing next to the A. Muscaria and has similar habitats and seasons. Confusion between those two, or exchange, is plausible, plus the fact that the color of the Boletus is brown, and the colors in ancient cultures were not one-to-one unequivocal, so it may be a description for a brown mushroom as red.
Wasson argues that the mycophobic attitude toward mushroom eating is due to this St. Augustine’s writing, or at least it influences St. François de Sales and Jeremy Taylor condemning it.