I've been reading a good book called The Republic of Shade, which is about the American Elm. It gives some really useful history that I'll be able to use in this next book. People of my age just barely remember all the elm-lined streets. By the time I was in college, they were all gone, devastated by Dutch Elm Disease. It was estimated that 77 million elms were killed. The worst hit areas were Massachusetts, Connecticut, Rhode Istand, and the rest of the Northeast, but there was also a very high concentration of elms in St. Joseph and Kansas City, Missouri, where I was raised. It was a big deal.
But now, it's happening all over again, with the ash trees that were planted to replace the elms. This disease is less picky about what species it hits, attacking all the species of ash. There are 7.5 billion ash trees in North America, and this disease could kill virtually all of them.
When will we learn that monocultures of any plant, whether it be urban trees or strawberries and potatoes, are prime targets for some hungry insect, and all that those insecticides do, in the end, is poison US? Here is an article in Wikipedia that tells about this most recent holocaust: http://en.wikipedia.org/wiki/Emerald_ash_borer
Cartoon reprinted from Benson/The Arizona Republic