 Fusicoccins are diterpenoid glycosides produced by the fungus "Fusicoccum amygdali", which is a parasite of mainly almond and peach trees.It stimulates a quick acidification of the plant cell wall; this causes the stomata to irreversibly open, which brings about the death of the plant.Fusicoccins contains three fused carbon rings and another ring which contains an oxygen atom and five carbons.