Gary Paul Nabhan describes one of Nikolay Vavilov’s early experiences in Where Our Food Comes From:
He was on assignment from the czarist government to determine why Russian troops at remote garrisons were getting sick on the wheat flour in their rations.
Soon Nikolay arrived at the first garrison near the Iranian border, where he quickly surmised that the soldiers were being fed flour that included not only the ground grains of wheat, but the ergot-infested seeds of a weedy grass named darnel, as well. Ergot is a fungus that attacks the grass seeds, producing toxic but typically sub-lethal levels of lysergic acid, the naturally occurring drug that later became famous as LSD.
Nikolay quickly completed his official assignment by making a simple suggestion to the garrison commander: The men would probably stop hallucinating soon after he bought them some better-quality flour.
This was in 1917, decades before the discovery of lysergic acid.