by Elio — As you know, the potato blight caused wide­spread famine in potato-de­pen­dent, mid-19th cen­tury Ire­land. You may also be aware of a cur­rent mal­ady, sud­den oak death, that af­fects large num­bers of trees in the Pa­cific coastal states of the USA. And if you are in­volved in agri­cul­ture in any way, you have likely heard of...