Bugs in the Cranberry Bogs


How Cape Cod Farmers Squared Off against Pests and Kept Cranberries Sauce on Thanksgiving Tables

Last weekend, we took a trip to the Cape to tour a cranberry bog. It was brisk and blustery; the kind of weather that makes you put on your scarf and boots for the first time.

We left early on Saturday and were often the only car in sight on 195. The foliage, just starting to turn from yellow to orange, the phragmites in full plum-colored plumage–it’s the kind of beauty that only happens where the woods meet the sea, and we coastal New Englanders could easily take this repeat performance for granted. When we arrive, we trudge over an open field to get to the bog; the ground had a kind of bounce to it from a millennia of accumulated peat moss. The landscape is scrubby, wet, and the crispy brown color that grass takes-on after it has seeded. The open field soon takes a downward pitch and there it is: a bog full of floating  red and burgundy orbs. We raise our hands to shield our eyes from the sun and survey the scene; what we had thought was an open field is actually more of a complex system of bogs with small stretches of semi-solid peat paths for harvesters, human and mechanical,  to get around come harvest time. 

I have been reading a book about cranberries called Massachusetts Cranberry Culture, and in the final chapter the author makes mention of the pest control problems cranberry farmers have faced in the last 400 years.  Pest control was apparently a regular topic of conversation for English settlers who tried their hand at farming and cultivating cranberries in the 1600s. Some of their methods–like the use of ash–had been learned from the Wampanoag, so it’s safe to assume that the Wampanoag, too, had been trying to eradicate pests in the cranberry bogs.

English settlers were eager to capitalize on the cranberry’s ability to ward-off scurvy; a remedy that wealthy sea captains were eager to purchase in the early days of transatlantic trade.  In the Cape, cranberries are still big business.  Just think of how many cans of cranberry sauce are sold around Thanksgiving alone; now think of those day-after-Thanksgiving-turkey sandwiches.  On that one holiday alone, each household in the United States is using at least two cans of cranberry sauce. (And if you’re like us, you love cranberries in chicken salad, too.) Canned cranberry sauce alone generates $125 million in sales a year.

That’s a LOT of cranberry sauce to come from one small corner of the United States.

Now, think of all the cranberry juice.  (Did you know that John F. Kennedy, a Cape Cod native, drank it daily in the White House?)

You see where I’m going with this: Cranberries are a major revenue stream for the Cape. And it turns out, the Cape is the perfect environment to grow cranberries. Cranberries like boggy, sandy soil. In fact, if you try to grow them in good soil, the plants will never actually generate fruit.

One of my favorite quotes about cranberries comes from the text Massachusetts Cranberry Culture by Robert S. Cox:

Well attuned to a Spartan life; the American cranberry is just the sort of fruit to make a stingy New Englander proud, making do with little and making little show of it.

There’s only one problem: pests love cranberries, too.

As far back as 1830, there’s mention of the “nefarious cranberry fireworm” destroying cranberry bogs.

In the early 1900’s Henry J. Franklin at the University of Massachusetts put together a roster of pests that were attacking cranberries from every angle:

Worms, weevils, blunt-nosed leafhoppers, and mites attack the foliage, buds, flower, and fruit; the cranberry girdler and spittle insects attack the stem of the plant, and at the root a steady army of attacking cranberry white grubs, grape anomala, cranberry root grubs, and striped colaspis.

Thankfully, some of these pests can be easily remedied: flood the bog at just the right time, and the moths can’t lay their eggs on the cranberry plants. No eggs means no voracious larvae. But flooding only remedies a few of the pest control problems. Cape Cod cranberry farmers had to stubbornly persist and seek out solutions in a practical and methodical way (as we New Englanders are apt to do).

In the 1840’s, it was common for cranberry farmers to spread a mix of salt, wood ashes, and lime. Others would sprinkle “tobacco water”–a method that organic cranberry growers still use today. Others, perhaps angrier, mixed sawdust soaked in kerosene. Some farmers even tried creating lures to draw away the pests: they would mix molasses and water in buckets, hoping the pests would drown (but they almost never did).

Some farmers encouraged bluebirds to nest on their farms, as bluebirds are “one of the greatest destroyers of small caterpillars and worms.” Other farmers imported European house sparrows and released them on their farms to eat the vine worms (these sparrows are now considered an invasive species). Other native birds that were found to be helpful were swallows, swifts, purple martins, phoebes, and red-winged blackbirds.

In the 1890’s synthetic pesticides started to be used broadly. Most of these pesticides were arsenic-based and were known by their colorful and exotic names: Paris Green, and London Purple were the most popular. These arsenic-based pesticides were mixed with molasses to make the arsenic stick to the leaves of the cranberry plant. These pesticides were effective, but farmers (and consumers) were concerned about using arsenic year-after-year on their land.

What does pest management in the Cape’s cranberry bogs look like today?

Today, cranberry bog farmers use Integrated Pest Management (IPM) to eliminate pests in bogs. IPM uses all available means to control pests in an environmentally conscious and economically sustainable manner.

  1. Cultural Controls: Strategies include holding late water floods,  sanding, proper timing of irrigation, and good drainage. All of these practices upset the natural lifecycle of cranberry pests. Flooding is useful for relieving insect pressure by killing problem insects. Sanding, which is done every three to five years, works to cover up old organic material underneath the vines. Burying this layer in sand impedes weed germination and insect reproduction thus giving the cranberry vine an advantage.
  2. Biological Controls use other organisms to eliminate problem pests. The use of nematodes to control certain pests or the use of B. thuringiensis bacteria for caterpillar control.
  3. Mechanical Controls control pests by physically removing them. Hand weeding and removal of pests is a commonly used mechanical control.
  4. Chemical Controls include the use of insecticides, herbicides, and fungicides.

Because the cranberry industry has cultural, biological, and mechanical controls as tools it has been able to reduce, though not eliminate, its reliance on pesticides. Chemical controls remain an effective tool and are essential to provide an adequate supply of food at a sustainable price.

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