A Blight By Any Other Name

When I was in college I took a semester course on “Dendrology,” the study of trees. We spent most of our class time–three hours every Friday afternoon–wandering the cross country trails looking at and measuring trees. The upshot of this class (other than the fact that I received academic credit for what felt a whole lot like recreation) was that I learned a lot of tree names in Latin. For a while, I could drop names like Liquidamder styraciflua and Fagus grandifolia  without blinking, but my repertoire has since shrunk to the point where, well, you’ve seen it all.

There is, however, one Latin name that I have since learned, and am unlikely to forget: Phytophthora infestans.  More commonly known as Late Blight, Phytophthora is a water mold (similar to a fungus) that decimates potatoes and tomatoes.  I know this all too well from the 2009 season, when Late Blight traveled through New England like the vegetative Grim Reaper, leaving sad little rotted tomato plants and despondent farmers in its wake.  The farm where I worked was no exception; the same week that we harvested our first tomatoes, the blight arrived, and within days our entire crop was ruined.  I mention Phytophthora because I just re-encountered it in a most unexpected place: my bedroom.

For Christmas, Andrew gave me a new book, 1493, the sequel to 1491, which I had read and thoroughly enjoyed last year.  Whereas 1491 devoted its pages to an exploration of the Americas before Colombus (soooo different from everything you learned in school!), 1493 investigates the ecological, social, and political changes wrought by the exchange of raw materials and finished goods between the Americas and the rest of the world.  Does my description make the book sound dry?  It most certainly is not.

Case in point–last night, reading in bed, I arrived at the chapter devoted to  Phyophthora infestans.  As you may recall, the Potato Blight in Ireland caused one of the worst famines in history, lasting from roughly 1845 until 1852.  The severity of the famine was made that much worse due to the fact that four out of every ten Irish people ate no solid food other than potatoes.  (An interesting side note–potatoes and whole milk are actually a complete and nutritionally balanced diet!  Of course, not if all the potatoes are blighted…)  1493‘s reports on the horrors of Ireland’s potato famine put my summer of tomato in famine in perspective.  Many farmers suffered financially that summer, but no one that I’ve heard of starved.

What I found interesting, however, was the author’s exploration of the reasons for the Blight’s apocalyptic agricultual effect.  While the sheer number of potatoes growing in Ireland made it an easy target, another, often overlooked   contributor may have been a change in Irish growing methods.  In the Andes, home of both the potato and the blight, crop failures seem to have been uncommon, and unheard of on the scale of the Great Hunger.  In the Andes, farmers grew countless varieties: blue potatoes, red potatoes, huge lunkers and tiny fingerlings, and many potatoes were grown from seed, rather than (as is common today) from genetically identical “seed potatoes” (actually potatoes that have been cut into chunks for planting).  While the Irish lacked the genetic diversity of the Andes, they did initially utilize strikingly similar field practices.  In both Ireland and South America, farmers planted on wide raised beds, separated one from the next with deep furrows for walking.   Raised beds create a particularly beneficial microclimate for crops in cold, wet environs.  Water and cold air are both drawn away from the plants and into the furrows, thereby decreasing the likelihood of blight transmission by half.

Unfortunately for the Irish, the 1830s witnessed a wave of agricultural innovation and a national campaign to move away from labor intensive hand cultivation toward standardized, mechanized row crops.  Ireland shifted from raised beds to flat beds, setting the stage for the Blight’s fantastic rampage.  In fact, scientists speculate that the Blight traveled to Europe through the guano trade, a harbinger of the move from low input agricultural to modern industrial farming.  Guano ships from Peru likely picked up a few blighted potatoes, which infected a ship’s worth of fertilizer, which in turn infected all of Western Europe, to a greater or lesser extent.

So, as a good little student of history, hard at work planning her spring fields, I’m taking notes to avoid any famines of my own.  If all else fails, we can always eat sweet potatoes!

One response to “A Blight By Any Other Name

  1. MK, I really enjoy this blog. Thanks for the history of the Irish Potato Famine. I never knew the details.
    Auntie Margaret

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