Scientists tell us that insects are humanity’s greatest rival for the world’s food resources, both directly – by eating the plants that we also want to eat – and indirectly – as carriers of disease-causing microorganisms. While some insect species are helpful – like bees, ladybugs, silk worms, the ground beetle and aphis – the majority are pests.
For centuries, a plague of locusts was one of the worst things that could happen to a society. They would descend on almost any kind of crop and devour it.
During the Depression of the 1930s, swarms of grasshoppers were described in Biblical terms when they descended on farmers who had already endured economic and environmental collapses. For some, it was the last straw because there was no effective way to combat the swarms.
Around that same time, cattlemen in Texas were battling screwworms, flies, ticks and grubs that were infecting herds.
In 1845, over half of the Irish potato crop was devastated as leaves turned black and the potatoes fermented within days of harvest. At the time, the Irish were dependent on potatoes for the majority of their diet, and so up to a million people died. Two million left the island for England, Canada and the U.S.
It wasn’t for another 100 years that scientists figured out that the blight was caused by a fungus. It wasn’t until 2001 that genetic fingerprinting showed that the fungus had been inadvertently imported to Europe from South America.
During the middle of the 20th century the same research boom that produced new hybrids, machines and technologies also produced insecticides, bactericides, miticides, rodenticides, nematicides and fungicides.
Today, including all pesticides, there are approximately 875 active chemical ingredients that are being formulated into about 21,000 registered commercial preparations. About 200 of those active ingredients account for 90 percent of the agricultural use in the U.S.
The chemicals can be divided into several classifications –
- Chlorinated hydrocarbons, such as chlordane, aldrin, dieldrin and heptachlor.
- Organic phosphates, such as parathion and malathion.
- Carbamates like bendiocarb.
- Systemic materials that can be targeted at specific organisms, including pyrethroids, suflonylureas and imidazolinones.
Paul Underwood (left) says that developments in fertilizer technology actually spurred the need for insecticides. “When we come in into the 60s,” he remembers, “all of a sudden commercial fertilizer is available. Okay, now we’re planting corn one year, planting corn the next year, planting corn the third year. Now all of a sudden we’ve brought in insects.” Paul knows first hand that monocultures can make attractive targets for certain pests like rootworm.
“Insecticides are very important,” Paul Stork (right) argues, “because there are over 10,000 types of insects as well as 1,800 different kinds of weeds and 1,500 kinds of fungus that attack crops every day.” In this video segment, he demonstrates what apples might look like without insecticides.