Garlic

Bulb of Allium sativum, a vegetable of the onion family rich in sulfur compounds.

Characteristics

Intact cloves contain alliin, a sulfur-containing derivative of cysteine.
Crushing releases the enzyme alliinase, which forms allicin within about a minute.
Allicin breaks down into diallyl sulfides; in oil it yields ajoene.
Traditionally used in plant purines and macerations in agroecological literature.

Role in the preparation: Crushed cloves are macerated in water, alcohol or oil to extract their sulfur compounds.

Caution: Prepare in a ventilated place, avoid splashing juice on the face and check local regulations before any use on crops.

Sources: Linus Pauling Institute, Oregon State University – Garlic

Documentary information: this is neither a recommendation for use nor a plant-protection or veterinary claim. Check your country's regulations before any use.