Toxic fungus infiltrated human food disguised as part of rye grain


You've probably heard about ergot—the plant fungus that naturally produces derivatives of LSD. Consumption of ergot spores can cause hallucinations (although, it must be said that eating ergot spores isn't the same thing as taking LSD, and not likely to produce the same sort of hallucinogenic experience). That connection to acid has led some historians to blame ergot for everything from the Salem witch trials to the French revolution. Those connections are more speculation than anything else, but ergot did make many people sick in Europe and North America. That fact has always led me to wonder why people ate ergot-tainted grain to begin with. As you can see in the photo above, the black pods of fungal spores are easy to spot. And they can be removed easily. So why wasn't that done historically?

The Scientist Gardener, a genetic engineer and gardening hobbyist, offers an interesting answer to that question: Historically, ergot infection was so common that at least some Europeans didn't know the spores weren't a part of the food crop they grew on.

Ergot is a plant disease caused by Claviceps purpurea, a member of one of my favorite fungal families, the Clavicipitaceae. Its lifecycle begins in the spring when infective spores are forcibly ejected from reproductive structures that sprout from overwintering pods of black, hardened mycelium called "sclerotia." These spores are launched into the air in the same season that rye and other susceptible grasses are flowering and float on the breeze until they come in contact with one of these plants. Upon landing on a susceptible flower's stigma, the spore germinates and grows into the ovary, destroying it and growing into a fluffy mass of hyphae – covered with asexual spores and a nectar-like substance that encourages insects to track it to yet to be infected flowers elsewhere.

While spores continue to infect new rye flowers, our original fungal infection continues to develop – growing into a long, thin and progressively harder pod where a particular rye grain should have been. One or many of these sclerotia (aka "ergots") may be found in any given rye head, where their little black nubs can be seen poking out of the head.

While we're well aware of the danger inherent in these little black pods today (and can remove them from infested grain), Medieval Europeans were not so fortunate. Ergots were routinely milled into flour, and in bad years could reach frighteningly high levels. The ergots were not identified as a source of this disease until 1670 (partially because these little sclerotia were so common that they were included in botanical illustrations of rye!)

Image: Dominique Jacquin via CC