Pesticide

Pesticides are substances used to control pests. They include herbicides, insecticides, nematicides, fungicides, and others. Herbicides are the most common.

Most pesticides are used to protect plants. They help crops grow by keeping away weeds, fungi, and insects. They work by using a chemical or a biological agent like a virus, bacterium, or fungus.

Pesticides help us grow more food, but they can be dangerous sometimes. It is important to use them carefully.

Definition

The word pesticide means something that stops or controls pests.

The Food and Agriculture Organization says a pesticide is any substance or mix used to stop, hurt, or control pests. Pests can be tiny creatures that spread sickness, unwanted plants or animals, or anything that damages food, wood, or animal feed when it is made, stored, or moved. Pesticides can also help plants grow better, make leaves fall off, or thin out fruit. They are used on crops before or after harvesting to keep them fresh during storage and transport.

Pesticides can be sorted by what they target, like herbicides for plants, insecticides for bugs, and fungicides for fungi. Some come from living things and are called biopesticides. Some pesticides were stopped from use many years ago, except in special cases like fighting malaria vectors.

History

For a long time, people used simple things from minerals and plants to keep pests away. These included things made from copper, arsenic, and sulfur, as well as plant-based materials like pyrethrum and nicotine. Some of these are still used today in farming.

In the 1940s, scientists made new chemicals such as DDT and 2,4-D. These worked well but later caused problems because they stayed in the environment and moved through the food chain. This was talked about in the book Silent Spring. Because of this, many countries stopped allowing DDT and other similar chemicals in the 1970s.

Over time, farmers have found better ways to use these chemicals. They now use a method called Integrated Pest Management, which means they only use pesticides when needed. This helps protect crops while using fewer chemicals. With new types of crops and plants, fewer insecticides are needed today. Organic farming, which avoids synthetic chemicals, has also become more popular.

Development of new pesticides

Scientists work to make new pesticides that work well and are safer for nature. They test many different things to see if they can stop pests like insects, fungi, or plants. Some of these come from nature, and others are made in labs.

If something looks good, it goes through many tests and changes to make sure it is safe and works well. Before a new pesticide can be used, it must follow strict rules set by regulatory authorities. This can cost a lot and take a long time. Because of this, finding new pesticides has become harder in recent years.

Uses

Pesticides are used in agriculture and many other places to control harmful creatures. They help stop mosquitoes from spreading diseases like West Nile virus, yellow fever, and malaria. They can also remove bees, wasps, or ants. Insecticides protect animals from sickness caused by parasites like fleas. Pesticides keep food safe by stopping moldy food or diseased produce from making people sick. Herbicides clear weeds from roadsides and can remove invasive weeds that harm the environment. They are also used in ponds and lakes to control algae and plants. Pesticides protect buildings from damage by pests like termites and mold. They are used in stores to keep rodents and insects away from food. They are also used on lawns and golf courses to keep them looking nice.

Integrated pest management uses many ways to control pests and is used in places like Indonesia, China, Bangladesh, the U.S., Australia, and Mexico. This method looks at how actions affect nature.

Every use of a pesticide has some risk, but using them properly makes these risks small enough for groups like the United States Environmental Protection Agency and the Pest Management Regulatory Agency of Canada to say it is okay.

DDT was sprayed inside houses to fight malaria mosquitoes since the 1940s, and the World Health Organization suggests this method. But DDT and other similar pesticides have been banned in most countries because they stay in the environment for a long time and can be harmful to people.

Amount used

In 2023, farmers around the world used about 3.73 million tonnes of pesticides to protect their crops. This amount was a little smaller than the year before but much larger than ten years ago. Brazil used the most pesticides, more than any other country. The United States was the second largest user.

The amount of pesticides used depended on how much land was being farmed. For example, Vietnam used much more per area than Russia. In the United States, the use of a certain type of pesticide has gone down a lot since 1980, mainly because farmers changed the way they grow corn.

Benefits

Pesticides help farmers grow more food. When farmers use pesticides, they can get more crops. Without pesticides, crop yields drop.

Pesticides have two kinds of benefits. The first kind are direct gains, like better crop yields and healthier plants and animals. The second kind are longer-term benefits, such as helping control diseases and protecting structures from damage. Farmers also benefit because they can grow more crops and sell them year-round, which helps keep food affordable for everyone.

Disadvantages

Using pesticides can affect both the environment and human health. Rules and education try to protect people from pesticide misuse, but not all misuse can be stopped. Using fewer pesticides and choosing safer ones can help protect people and nature.

Health effects

Most health worries about pesticides come from using them directly, like farmers or gardeners do. Tiny amounts of pesticides on fruits and vegetables are thought to be safe.

Using pesticides at work can sometimes harm health. Some studies link certain pesticides to changes in the brain and nervous system. There is some evidence that some pesticides might affect birth outcomes, but more research is needed.

Environmental effects

Pesticides can harm the environment in several ways. They often affect more than just the pests they target and can spread to air, water, and soil. This spread, called pesticide drift, can pollute areas far from where the pesticide was used.

Pesticides can reduce the number of helpful insects and animals, harm birds, and threaten plants and animals at risk of disappearing. Sometimes, pests can become resistant to pesticides, meaning stronger or more pesticides are needed, which creates more pollution.

Economics

Pesticides help increase food production but also come with costs. In the United States, the benefits of pesticides in farming are much greater than the health and environmental costs. However, registering a new pesticide can take many years and cost a lot of money. Farmers and pesticide companies share these costs.

Resistance

When we use pesticides, pests can sometimes become resistant to them. This means the pesticides may not work as well later. There are ways to use pesticides that can help slow down resistance. The natural behavior of pests and their environment can also affect how quickly resistance happens.

Alternatives

Alternatives to pesticides are ways to control pests without using chemicals. These include changing how we grow plants, using natural enemies of pests, and using technology. For example, growing different plants together or changing when and where we plant can help keep pests away.

Other methods use natural organisms that fight pests, such as certain fungi, bacteria, or viruses. There are also ways to stop insects from having babies by releasing sterilized males. These methods can be just as effective as chemicals and are often safer. Some studies show that using compost or special plant foods can help control pests and improve crop growth.

Types

Biopesticides

Main article: Biopesticide

Biopesticides are special kinds of pesticides made from natural things like animals, plants, bacteria, and minerals. Examples include canola oil and baking soda. Biopesticides are divided into three main groups:

• Microbial pesticides made from bacteria, entomopathogenic fungi, or viruses. Entomopathogenic nematodes are also often included.
• Biochemical pesticides or herbal pesticides are natural substances that help control pests and diseases.
• Plant-incorporated protectants (PIPs) have genes from other species added to their own genes (i.e. GM crops).

Regulation

International

In many countries, pesticides need to be approved by a government agency before they can be sold or used.

Most countries have rules about how to store pesticides safely, and many also have rules for getting rid of old pesticides properly. In 1985, the United Nations Food and Agriculture Organization made guidelines to help countries make better rules for pesticides. These guidelines were updated in 1998 and 2002 to help protect people and the environment.

United States

In the United States, the Environmental Protection Agency (EPA) makes sure pesticides are safe to use. They check that pesticides do not harm people or the environment, especially children. All pesticides go through many tests before they can be used. Some pesticides are too dangerous for everyone to use, so only trained professionals can handle them.

Besides the EPA, the United States Department of Agriculture (USDA) and the United States Food and Drug Administration (FDA) also set rules about how much pesticide can be left on food.

Canada

Main article: Pest Management Regulatory Agency

EU

Main article: Regulation of pesticides in the European Union

European Union laws have banned some of the most dangerous pesticides. In 2023, European leaders decided to cut pesticide use in half by 2030, especially the most harmful ones, and to encourage farmers to find safer ways to protect their crops.

Residue

Pesticide residue is the tiny bit of pesticides that can stay on or in food after it has been treated. Rules are made to keep these amounts safe for people to eat. These rules help make sure that the food is safe by waiting a certain time before picking crops that have been treated.

Some older pesticides are no longer used because they stay in the soil for a very long time. But, these older pesticides can still be found in very small amounts in people today. In 2016, most food in the United States either had no pesticides left or had very little, well below the safe levels set by rules.