Hydrogen Cyanide Fumigant
Definition - What does Hydrogen Cyanide Fumigant mean?
Hydrogen cyanide (HCN) is a colorless, flammable and poisonous liquid sometimes used in vineyards as a fumigant against insects. It can be extremely toxic and must be used with care and in proper concentrations. If utilized to combat insects against damaging vineyards (or other plant life), it must be used in the evening, as it can interrupt photosynthesis when sprayed in the morning.
WineFrog explains Hydrogen Cyanide Fumigant
Hydrogen cyanide, also called prussic acid, is a chemical compound produced on an industrial scale with many uses. It is an insecticide and rodenticide with a "bitter almond" odor.
Its production on a massive scale began in the late 1800s and was used in silver and gold mining. It exists naturally and can be obtained from the pit of many fruits like apricots, apples, cherries and bitter almonds.
HCN has also proven to stimulate growth in some species of plants in low concentrations. However, it must be used when there is minimal water on plant foliage, as it can dissolve in water and become acidic, causing irreversible damage to plants. It is important not to spray HCN on the fruit set (or any fruit) once it has developed because it can be poisonous to any animal that would consume it.