Pesticide facts for kids

A self-propelled crop sprayer spraying pesticide on a field

A crop-duster spraying pesticide on a field

Pesticides are special substances used to control unwanted organisms called pests. These pests can be insects, weeds, fungi, or other small living things that harm plants, animals, or even our homes. Pesticides help protect crops from damage, which means farmers can grow more food. They also help prevent diseases spread by insects like mosquitoes. However, it's important to use pesticides carefully because they can also affect humans and other helpful creatures if not handled properly.

What Are Pesticides?

The word pesticide comes from two Latin words: pestis, meaning 'plague' or 'harmful thing', and caedere, meaning 'to kill'. So, a pesticide is literally something that kills pests.

Pesticides are designed to target specific types of pests. Here are some common types:

How Pesticides Work

Pesticides can be chemicals or even natural living things like certain viruses or bacteria. They work by stopping pests from growing, moving, or reproducing. Some pesticides stay on the surface of plants and kill pests on contact. Others are systemic, meaning they are absorbed by the plant and move inside it, protecting it from within.

Pesticides are also classified by how they affect pests. This helps scientists understand how to use them best and prevent pests from becoming resistant to them.

Some pesticides break down quickly in the environment, while others last longer. Today, scientists try to create pesticides that do their job and then break down safely, so they don't harm the environment for a long time.

A Look Back: The History of Pesticides

For a long time, people used natural substances or simple chemicals to protect their crops. Things like copper and sulfur were common, along with plant extracts from flowers like pyrethrum. Many of these older, less harmful methods are still used in organic farming today.

In the 1940s, new types of pesticides were created, like DDT. These were very powerful and helped farmers grow more food. However, people soon realized that some of these new chemicals could stay in the environment for a very long time. They could even build up in the food chain, affecting animals and people far away from where they were used.

A famous book called Silent Spring in the 1960s helped everyone understand these environmental concerns. Because of this, many countries eventually banned DDT and other long-lasting pesticides. Now, scientists work hard to develop pesticides that are effective but also break down more quickly and safely in nature.

Over time, farmers learned to use pesticides more wisely. They started using a method called Integrated pest management (IPM). This means they only use pesticides when absolutely necessary, and they combine different ways to control pests, like using natural enemies or choosing resistant plants. This helps reduce the amount of pesticides needed.

Today, pesticides are much more effective than they used to be. Farmers use smaller amounts to protect their crops. Also, new technologies like genetically modified crops have helped reduce the need for some insecticides.

Creating New and Better Pesticides

Scientists are always working to find new and improved pesticides. The goal is to create products that are very good at controlling pests but cause less harm to humans and the environment. They also look for new ways to fight pests that have become resistant to older pesticides.

Developing a new pesticide is a long and expensive process. It involves many tests to make sure the new substance is effective and safe. Scientists test thousands of compounds to find just a few that might work. They also try to make sure these new pesticides break down easily after they're used.

Recently, there's been more interest in biopesticides. These are made from natural materials like plants, animals, or bacteria. They are often safer for the environment and cheaper to develop, which is exciting for the future of pest control.

How Pesticides Are Used

Pesticides are used in many places, not just on farms. Their main job is to control organisms that cause problems.

• Protecting Crops: Farmers use pesticides to keep weeds, fungi, and insects from damaging their crops. This helps ensure we have plenty of healthy food to eat.
• Controlling Diseases: Some pesticides help control insects like mosquitoes that can spread serious diseases such as malaria. This saves many lives around the world.
• Keeping Homes Safe: Pests like termites and mold can damage houses and other buildings. Pesticides help protect these structures.
• Maintaining Public Spaces: Herbicides are used to clear unwanted plants from roadsides, parks, and golf courses. They also help control algae in ponds and lakes, making them safer and more pleasant for swimming and fishing.
• Food Storage: In grocery stores and food warehouses, pesticides help prevent rodents and insects from spoiling food supplies.

Many places now use Integrated pest management (IPM). This smart approach combines different methods to control pests, reducing the need for chemical pesticides. It helps keep the environment balanced and healthy.

How Much Pesticide is Used?

Pesticide use worldwide, by country in 2023

Pesticide use by region

Pesticide use per cropland area by region

The amount of pesticides used worldwide has increased over the years, especially as the global population grows and more food is needed. In 2021, about 3.54 million tonnes of active pesticide ingredients were used in agriculture globally. Brazil and the USA were among the largest users.

However, modern pesticides are often more powerful, so farmers can use smaller amounts per area than in the past. This is a positive step towards reducing their environmental impact.

The Good Side of Pesticides

When used correctly, pesticides offer several important benefits:

Helping Plants and Animals

• More Food: Pesticides help farmers grow more food by protecting crops from pests. This means there's enough food for everyone and it can be more affordable.
• Better Quality: They help improve the quality of crops and livestock by preventing damage and diseases.
• Stopping Invasive Species: Pesticides can control invasive species – plants or animals that are not native to an area and can harm the local environment.
• Protecting Health: By controlling insects that spread diseases, pesticides help keep people and animals healthy.
• Saving Structures: They protect buildings and other structures from damage caused by pests like termites.

Economic Benefits

The pesticide industry is a large global business. In 2018, worldwide sales were estimated at $65 billion. For every dollar spent on pesticides for crops, farmers can save several dollars worth of crops that would otherwise be lost to pests. This helps farmers earn a living and provides consumers with a wide variety of affordable food year-round.

The Challenges and Risks of Pesticides

While pesticides offer many benefits, it's also important to understand their potential drawbacks. Using pesticides comes with responsibilities to protect both people and the environment.

Health Concerns

A sign warning about potential pesticide exposure

The biggest health concerns usually come from direct contact with pesticides, especially for people who work with them regularly, like farmers. If not handled carefully, pesticides can cause various health issues, such as affecting the body's systems or causing skin irritation. Scientists are always studying these effects to make sure pesticides are as safe as possible.

It's important to remember that the amount of pesticide residue found on fruits and vegetables is usually very small. Regulatory agencies carefully check these levels to make sure they are safe to eat.

To prevent health problems, it's crucial to use pesticides exactly as instructed. This includes wearing protective gear and allowing enough time before re-entering treated areas. Training and clear labels help everyone use these products safely.

Environmental Impact

Pesticides can also affect the environment. When sprayed, a lot of the pesticide might not reach its target. It can drift in the air, land on other plants, or get into water and soil. This can harm helpful insects, like bees, which are important for pollinating plants. It can also affect birds and other wildlife.

Older, long-lasting pesticides like DDT were banned because they stayed in the environment for many years and spread widely. Today, new pesticides are designed to break down more quickly, reducing their long-term impact on nature. Scientists and regulators work to ensure that pesticides degrade safely and don't build up in the environment or the food chain.

Economic Costs

Besides the benefits, there are also costs associated with pesticides. These include the money spent on developing and buying them, and the potential costs of environmental cleanup or health care if they are misused. For example, in the United States, the environmental and health costs from pesticides were estimated to be around $9.6 billion annually, though this is offset by much larger gains in agricultural production.

Pests Can Become Resistant

Just like bacteria can become resistant to medicines, pests can also become resistant to pesticides over time. This means a pesticide that once worked well might stop being effective. To prevent this, farmers and scientists use different strategies, like rotating different types of pesticides or using IPM methods.

Other Ways to Control Pests

Many methods exist to control pests without relying solely on chemical pesticides. These alternatives are becoming more popular and can be very effective:

Smart Farming Methods

• Mixing Crops: Growing different types of plants together (called polyculture) can confuse pests and make it harder for them to spread.
• Crop Rotation: Changing the crops grown in a field each season helps break the life cycles of pests that might specialize in one type of plant.
• Timing is Key: Planting crops at certain times can help avoid periods when pests are most active.
• Trap Crops: Farmers can plant special 'trap crops' that attract pests away from the main crops they want to protect.

Using Nature's Helpers

• Natural Enemies: Releasing beneficial insects that are natural predators or parasites of pests can help keep pest numbers down.
• Biopesticides: These are pesticides made from natural materials like bacteria, fungi, or plant extracts. They are often safer for the environment.

Advanced Techniques

• Genetic Engineering: Some crops are specially bred or engineered to be resistant to certain pests, reducing the need for insecticides.
• Sterile Insect Technique: For some insects, scientists can sterilize male insects and release them. When these males mate, they don't produce offspring, which helps reduce the pest population over time.
• Robots and Lasers: New technologies, like robots that use lasers to zap weeds, are also being developed!

These alternative methods, often combined in IPM, can be just as effective as chemical pesticides and help create a healthier environment.

Different Kinds of Pesticides

Pesticides come in many forms, each designed to tackle a specific type of pest or problem.

Biopesticides: Nature's Way

Biopesticides are special types of pesticides that come from natural sources. These can be animals, plants, bacteria, or certain minerals. For example, canola oil and baking soda can act as biopesticides. They are often seen as a more environmentally friendly option.

• Microbial Pesticides: These use tiny living things like bacteria, fungi, or viruses to control pests.
• Biochemical Pesticides: These are natural substances that affect pests, like plant extracts or pheromones (chemicals that insects use to communicate).
• Plant-Incorporated Protectants (PIPs): These are plants that have been given special genetic material to help them protect themselves from pests.

Pesticides by Target Pest

Here's a list of pesticides named after the pests they target:

Rules and Safety: How Pesticides Are Regulated

Preparation for an application of hazardous herbicide in the US

Because pesticides can be powerful, governments around the world have rules to make sure they are used safely. These rules protect people, animals, and the environment.

International Rules

Many countries work together to create international guidelines for pesticides. This is important because pesticides and the foods they protect are traded across borders. Organizations like the Food and Agriculture Organization (FAO) help set standards for how pesticides are distributed and used. They also work to ensure countries share information about chemical safety.

Rules in the United States

In the United States, the United States Environmental Protection Agency (EPA) is in charge of regulating pesticides. They make sure that pesticides are safe for people and the environment, especially for children. Before a pesticide can be sold, it must go through many tests to prove it works and is safe when used correctly.

Every 15 years, all registered pesticides are reviewed to ensure they still meet the latest safety standards. Each pesticide comes with a detailed label that explains exactly how to use it safely and effectively. Some very strong pesticides are only allowed to be bought and used by trained professionals.

Other agencies, like the United States Department of Agriculture (USDA) and the United States Food and Drug Administration (FDA), also set limits on how much pesticide residue can be on food. This helps keep our food safe to eat.

Rules in Europe

The European Union (EU) also has strict laws about pesticides. They have banned many highly toxic pesticides, especially those that could cause serious health problems or harm the environment for a long time. In 2023, the European Parliament approved a plan to reduce pesticide use by 50% by the year 2030, especially the most hazardous ones. This plan also focuses on helping farmers find safer alternatives.

Pesticide Residues on Food

Pesticide residue refers to the tiny amounts of pesticides that might remain on or in food after crops are treated. Don't worry, regulatory authorities carefully set maximum residue limits (MRLs) to ensure these levels are safe for us to eat.

Farmers also follow rules, like waiting a certain amount of time after spraying before harvesting crops. This allows any residues to decrease to safe levels. Authorities regularly check food samples. For example, in 2016, over 99% of US produce samples had no pesticide residue or levels well below the safe limits set by the EPA.

See also

In Spanish: Plaguicida para niños

• Index of pesticide articles
• Environmental hazard
• Pest control
• Pesticide residue
• Pesticide standard value
• WHO Pesticide Evaluation Scheme