|There is more information available on this subject at Fungicides on the English Wikipedia.|
Fungicides are chemical compounds used to prevent the spread of fungi in gardens and agricultural land, which can cause serious damage resulting in loss of yield and thus profit. In the 21st century, most are harmful to Humans.
It appears that by 2524, fungicides are harmless to Humans, and no harmful effects occur other than the familiar cough or sneeze caused by the dust. The fungicide used on Harvest is a white, powdery substance that can coat Humans in such a thick layer of it that they end looking like ghosts.