Sunday, June 07, 2009

The bugs will always win

kw: book reviews, nonfiction, insects, history

My brother Mark is probably the best writer among my brothers and me. After a twenty-year career as a working calligrapher and freelance historical lecturer, he returned to school to earn a Doctorate, the credential he needed to gain a position as a curator. Calligraphy, based as it is in the history of written language, is a necessarily historical enterprise. He achieved a Masters' degree in History without difficulty, but was blocked from entering the doctoral program by jealous professors of history. He was already a published author, and his writing style put them to shame. He lucked out in another way, though; he'd been illustrating books for a prominent archaeologist, and was asked to join the doctoral program in the archaeology department. He got his doctorate in that. He is a college professor now.

The fact remains that it is hard to find a historian who is a good writer. James E. McWilliams is a bit better than the middle of the pack in that regard. I managed to read all of American Pests: The Losing War on Insects from Colonial Times to DDT, but it was a bit of a slog most of the time. I picked up the following:
  • Prior to the American Civil War, farmers were the primary students of insect ecology and control. The methods were mainly those that are now called "sustainable": adjusting the timing of plowing to destroy insect larvae or pupae, and of planting to miss their hatching, rotating crops so no one set of pests gains a year-upon-year advantage, planting decoy crops, and fostering plant enemies such as birds and parasitic wasps. Professional entomologists were few and worked closely with the farmers, helping them spread new knowledge mainly via farming journals.
  • From the Civil War to the 1930s, mainly stemming from the influence of Thaddeus Harris, pesticidal chemicals became increasingly popular, and agricultural entomology became increasingly organized under government control. Professional journals began to replace farm journals. The chemicals of choice were mainly arsenates, and the deadliest was lead arsenate. Paris green, a copper arsenate, was a favorite, being moderately effective and slightly less poisonous to humans than lead arsenate.
  • DDT was discovered in 1939, and synthetic chemicals, mainly organochlorides, enjoyed a twenty-year heyday. DDT is much less harmful to vertebrates than the arsenates, in comparison to the harm it does to insects, so such chemicals are safer, but not safe enough. The publication of Silent Spring in 1962 brought together scientific knowledge and public concern at just the right time to cause a revolution in public and political sentiment toward chemical pesticides.
The story the author doesn't tell is the continuing trend toward pesticides that are safer to use and less harmful to vertebrates, including ourselves. But some of the difference is window dressing. I remember as a boy sitting in a cherry tree with the orchard owner's son, eating cherries on which we could see the film of DDT. We knew when we got a headache, that was enough. I am not sure it is safe to do that with any modern insecticide.

I read recently, as an unsupported statement, that for several years the world has produced less food than the amount eaten, that we are using up our reserves. If this is so (I intend to find out), we need to increase production, and at this point, the "green revolution" of super-grains that need super-fertilizers has just about ended. Now we need to reduce the depredations of insects, which still consume a third to half of all crops in most of the world. The use of pesticides is certain to increase as human population increases.

The author didn't make much mention of resistance. This is an increasing problem. Just in twenty years, flies developed sufficient resistance to DDT that they could almost live off the stuff. Fortunately, mosquitos are still susceptible, and it is DDT and related chemicals that are staving off mosquito-borne malaria in much of the world (Yes, Virginia, DDT is not banned everywhere). The tropical regions that are still plagued by malaria are too poor to afford even cheap DDT, which is almost free, but costs quite a bit to apply. How will anyone ever drain all the swamps of Africa? Particularly now that draining swamps is considered an ecological no-no?!?

The primary reason insects are such a problem is our reliance on monocropping. The author makes it clear that many formerly rather innocuous insects became monsters when they were enabled to spread over acre after acre, upon plants that they seldom would eat before, but the new abundance allowed quick evolution of critters that could take full advantage of the "amber waves of grain." Today's world requires monocropping.

The author makes no mention of Malabar Farm, which I remember visiting in about 1962. Louis Bromfield's visionary sustainable farm, begun in 1939, is still a model of agriculture carried out to build the soil instead of depete it, and of using crop rotation and multicropping and other measures to minimize insect damage without resort to pesticides. I just don't know if a world of Malabar Farms can feed nine billion people. By 2050 we may know.

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