164 animal, vegetable, miracle
breathless suspense until—zoom—his flight dance climaxed suddenly in
a nosedive. We stood in the bronze light, impressed into silence. We could
hear other birds, which Elsie and David distinguished by their evening
songs: vesper and grasshopper sparrows, indigo buntings, a wood thrush.
Cliff swallows wheeled home toward their bottle- shaped mud nests un-
der the eaves of the barn. Tree swallows, wrens, bluebirds, mockingbirds,
great horned owls, and barn owls also nested nearby. All seemed as impor-
tant to David and Elsie as the dairy cows that earn them their living.
Elsie and David aren’t Audubon Club members with binoculars and a
life list, nor are they hippie idealists trying to save the whales. They are
practical farmers saving a livelihood that has been lost to many others
who walked the same road. They spare the swallows and sparrows from
death by pesticide for lots of reasons, not the least of which is that these
creatures are their pesticides. Organic farming involves a level of biotic
observation more commonly associated with scientists than with farmers.
Losing the Bug Arms Race
What could be simpler: spray chemicals to kill insects or weeds, increase
yields, reap more produce and profits. Grow the bottom line by spraying the cur-
rent crop. From a single- year perspective, it may work. But in the long term we
have a problem. The pests are launching a counterattack of their own.
Within one field, an application of pesticides will immediately reduce insect
populations but not eliminate them. Depending on the spray density and angle,
wind, proximity to the edge of the field, and so forth, bugs get different doses of
the poison. Those receiving a lethal dose are instant casualties.
Which bugs stay around? Obviously, those lucky enough to duck and cover.
Also a few of those who did get a full, normally lethal dosage, but who have a
natural resistance to the chemicals. If their resistance is genetic, that resistance
will come back stronger in the next generation. Over time, with continued spray-
ing, the portion of the population with genetic resistance will increase. Eventu-
ally the whole population will resist the chemicals.
This is a real- world example of evolution, and whether or not it’s showing up
in textbooks, it is going strong in our conventional agriculture. More than 500
species of insects and mites now resist our chemical controls, along with over
150 viruses and other plant pathogens. More than 270 of our recently devel-