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 current 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 spraying, the portion of the population with genetic resistance will increase. Eventually 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 developed herbicides have now become ineffective for controlling some weeds. Some 300 weed species resist all herbicides. Uh-ho, now what?
The standard approach has been to pump up the dosage of chemicals. In 1965, U.S. farmers used 335 million pounds of pesticides. In 1989 they used 806 million pounds. Less than ten years after that, it was 985 million. That's three and a half pounds of chemicals for every person in the country, at a cost of $8 billion. Twenty percent of these approved-for-use pesticides are listed by the EPA as carcinogenic in humans.
So, how are the bugs holding out? Just fine. In 1948, when pesticides were first introduced, farmers used roughly 50 million pounds of them and suffered about a 7 percent loss of all their field crops. By comparison, in 2000 they used nearly a billion pounds of pesticides. Crop losses? Thirteen percent.
Biologists point out that conventional agriculture is engaged in an evolutionary arms race, and losing it. How can we salvage this conflict? Organic agriculture, which allows insect predator populations to retain a healthy presence in our fields, breaks the cycle.
Steven L. Hopp
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 spraying, the portion of the population with genetic resistance will increase. Eventually 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 developed herbicides have now become ineffective for controlling some weeds. Some 300 weed species resist all herbicides. Uh-ho, now what?
The standard approach has been to pump up the dosage of chemicals. In 1965, U.S. farmers used 335 million pounds of pesticides. In 1989 they used 806 million pounds. Less than ten years after that, it was 985 million. That's three and a half pounds of chemicals for every person in the country, at a cost of $8 billion. Twenty percent of these approved-for-use pesticides are listed by the EPA as carcinogenic in humans.
So, how are the bugs holding out? Just fine. In 1948, when pesticides were first introduced, farmers used roughly 50 million pounds of them and suffered about a 7 percent loss of all their field crops. By comparison, in 2000 they used nearly a billion pounds of pesticides. Crop losses? Thirteen percent.
Biologists point out that conventional agriculture is engaged in an evolutionary arms race, and losing it. How can we salvage this conflict? Organic agriculture, which allows insect predator populations to retain a healthy presence in our fields, breaks the cycle.
Steven L. Hopp
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