You'd be surprised how easily 40% of the supply of a crop could disappear. P.E.I. produces 1/3 of all potatoes consumed in Canada (this includes virtually all potatoes used by McDonalds, Wendy's and most fast food companies). If a severe problem ever hit P.E.I. it would be devastating, and it's an island a whole factor smaller than the next smallest province and has less than .1% of Canadian land.

As the island only has 1 bridge connecting it to the mainland, and the ferry service is largely only a novelty service any more it would present a serious problem for the country for its food production.