Super Weeds: How Much Should We Worry About Pesticide-Resistant Weeds and Insects?

Super Weeds: How Much Should We Worry About Pesticide-Resistant Weeds and Insects?
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This war against nature has been waged with everything including traps, crushed chrysanthemum petals and scarecrows for pests; crop rotation, hand-pulling buds or leaves, and “miracle” pesticides, such as Roundup, for weeds.

Weeds, like cockroaches, have evolved to survive and farmers and other agri-producers spend an inordinate amount of time seeking to control them. Researchers have long speculated that the use of super chemicals on genetically modified plants would one day result in the emergence of “super weeds,” which are resistant to pesticides. Now it seems that day has arrived. How much of a problem is this and what is the solution?

History’s Oracle

Marine biologist and writer with the U.S. Fish and Wildlife Service, American icon Rachel Carson tried to tell the world decades ago the truth about the long-lasting poisons used in agricultural control programs. After long and careful deliberation, while being stonewalled by magazines and advertisers fearing reprisals to publishing her work, she wrote the book Silent Spring in 1962, a beautiful diatribe about a dreary subject, pesticides.

She was attacked by the chemical industry and threatened privately until President Kennedy set up a panel to study the problem of pesticides. Of course, the study was just the beginning of the justification of her thesis.

How Did This Happen?

If a farmer scrupulously follows the instructions on the pesticide label, his use of agricultural chemicals will produce no residues larger than permitted by the Food and Drug Administration. It’s similar to not overusing antibiotics, which has been shown to produce drug resistant “supergerms” that are difficult to control.

Setting aside the question whether these legal pesticide residues are safe, it remains a well-known fact that farmers frequently exceed the recommended dosages, put chemicals on too close to harvest time, and use several insecticides when one will do the job. Consequently, these higher dosages and haphazard combinations create a disturbing number of violations.

The Food and Drug Administration can only protect us to a limited extent, meaning its jurisdiction is only over foods shipped in interstate commerce. Foods grown and marketed within a particular state have their own purview of authority for safety. And, of course, the small number of federal inspectors means only a small percent of crop products can be checked.

Also, most states have woefully inadequate laws in this field. The problem of safety does not take into account accidental contamination in processing, packaging and transportation.

Farm Facts

Today the American farmer feeds about 155 people worldwide. In 1960, that number was 25.8. With more people to feed, the pressure is on to increase production and American farmers feel that chemical pesticides help to achieve this goal.

As a result, the United States is the leading producer of synthetic pesticides. Pesticide usage has more than doubled in the past twenty years, and it is the most widespread method for pest control. According to the EPA, “…Farmers spend approximately $4.1 billion on pesticides annually. They justify this high cost by a direct dollar return of from $3 to $5 for every $1 spent on pesticides.”

Pesticide Failure

At first, pesticides were hailed as miracle products. The insects were dying, diseases were contained, and crops were being saved. Then, after time, certain species of insects began to return and sometimes, in larger numbers. The pest resurgence began winning the chemical war. But why?

Originally, pests were killed in large numbers by the pesticides. But so were the natural enemies that eat the pests. Sometimes the pest’s enemies just left the field. Once the food returned however, the pests returned first, and began to propagate before their natural enemies returned to cull down their numbers.

The Tale of Sri Lanka

A female mosquito of the Culicidae family

In the early 1960s, a chemical known as DDT was used in Sri Lanka to control the mosquitos that carry malaria, a deadly illness. Six years in with the use of DDT, only seventeen cases of malaria were reported. But by 1970, there were an estimated four million cases.

The malaria-carrying mosquitos had built up a resistance to DDT because not all the insects were killed during a single application. Others just seemed more tolerant. Then, when the survivors reproduced, they passed on their resistance to their offspring—the next generation.

When insects become resistant to chemicals, they can also become resistant to another pesticide that is chemically similar in a phenomenon called cross-resistance. Some species can literally become immune to everything thrown at them, or a new species may develop.

The Enforcers

The widespread use of pesticides affects humans—but how, and the long-term consequences, are always in question and debate. Even though in 1947 the government instituted regulation over the pesticide industry with the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the emphasis was on increasing yields instead of anticipating the data necessary for assessing the chemicals.

Twenty years later, when information on the potential side effects to toxic chemicals became more in tune with the environment, health risks and birth defects, the EPA could not keep up. A 1984 National Academy of Sciences study showed that of 3,350 pesticides and their inert ingredients, only 10 percent had been evaluated.

A Farmer’s Future Options

These are the things that farmers of the future can do to limit their use of pesticides. Some of them are already in the developmental stage.

Biotechnology: Scientists can manipulate genetically-engineered bacteria living inside crop plants that can churn out desirable chemicals such as insect and fungus deterrents, along with growth-enhancing nutrients.

Develop disease-resistant plants: Genetic engineering may also be used more, to develop highly specific insect pathogens—agents of disease—to affect an insect’s immune system, thus killing them off.

Computer data and modeling: More up-to-date computer information can provide results of the latest success and advice on controlling pests.

Biological control: Scientists can seek ways to mass-produce species of natural enemies through artificial diets, to ensure that the “good bugs” outnumber the “bad bugs.”

Selective Chemicals: More selective chemical additives such as insecticidal soaps mixed with small amounts of pesticide are helpful. These soaps control pests and keep the pesticide mixture on the plants longer.

What You Can Do

Outdoor farmers’ market

Reduce your own risk to pesticides by washing your vegetables, tearing off the outer leaves, and trimming away any waxy coatings on cucumbers, peppers and apples, Let the preparation, such as trimming away fat from meat, and using low-fat or non-fat dairy products aid in the removal.

Choose a local, small farmers’ market. You can also buy organically-grown produce and choose products grown in season. Other countries’ products may not have the same pesticide regulations as ours. Also, don’t insist on perfect-looking produce—more pesticides are used to obtain this perfection.

We can’t change the fact that farmers will continue to use chemicals. As author Sally Lee says in her book, Pesticides, “If we want to save this environment and its inhabitants, the human ingenuity that created pesticides needs to create ways in which pest control measures and the environment can work together."