Biological pest control

Some bugs help us.

People can use these good bugs in three ways. They can bring new bugs to a place. They can add more bugs to a field. They can also help the bugs that are already there.

One kind of bug is a tiny wasp.

Long ago, people used ants to help fruit grow.

Biological control is a way to manage pests. Pests can be insects, weeds, or germs. Instead of using chemicals, people use living things to help. These helpers are called biological control agents.

There are three main ways to do this. The first way is called importation. This is when people bring a natural enemy to a new place. For example, a beetle was sent to California to save citrus trees.

The second way is called augmentation. This means adding more helpers to an area. People might release many lady beetles to eat aphids.

The third way is called conservation. This helps the natural enemies that are already there. They stay in the area to keep pests low.

Some helpers are parasitoids. These are tiny wasps that live inside or on a host.

Biological control is a clever way to manage pests. Pests can be insects, mites, weeds, or even germs. Instead of using harsh chemicals, people use other living things to help. These helpers are called biological control agents. They work through predation, which is when one animal eats another. They also use parasitism, where one organism lives on or inside another. This method helps keep the number of pests low. It is a very important part of modern farming and nature care.

There are three main ways this work happens. The first way is importation, also called classical biological control. This is when people bring a natural enemy to a new place where it does not live yet. The second way is augmentation. This means adding more helpers to an area to boost their numbers. This can be done by releasing a few to help them grow, or releasing many at once for a quick fix. The third way is conservation, which helps the natural enemies that are already living in the area.

People have used these tricks for a very long time. In ancient China, a book called "Nanfang Caomu Zhuang" described how people used ants to protect citrus fruits. These reddish-yellow ants were known as huang gan ants. Later, in the 1870s, modern methods began to grow in the United States. Scientists like C. V. Riley started moving tiny wasps to control crop pests. In 1873, the first international shipment happened when mites were sent to France. This was to help save grapevines from a tiny pest.

Many famous successes have happened around the world. In California, a lady beetle called the vedalia beetle was brought from Australia. It helped save the citrus industry by eating the cottony cushion scale. In Australia, the cactus moth helped destroy millions of hectares of prickly pear cactus. In Zimbabwe, a special weevil helped control a weed called giant salvinia. This control was 99 percent successful over two years. Even in Canada, wasps were released in 1882 to help with garden pests.

Biological control connects to how nature stays in balance. In a healthy forest or garden, predators keep other bugs from taking over. For example, lady beetles are common helpers that eat aphids. Some tiny wasps, called parasitoids, find moth eggs to stop them from hatching. Scientists even use new tools like drones to release these helpers today. However, we must be careful when moving species. If we do not understand the consequences, a helper might accidentally become a pest itself.

Biological control, often called biocontrol, is a method used to manage pests. Pests can be animals like insects and mites, or they can be plants like weeds. They can even be pathogens, which are organisms that cause disease in plants or animals. Instead of using chemicals, biocontrol uses other living organisms to control these pests. This process relies on natural mechanisms such as predation, where one animal eats another. It also uses parasitism, where one organism lives on or inside a host. Finally, it can use herbivory or competition to manage populations.

There are three primary strategies used in biological control. The first is classical biological control, also known as importation. This involves introducing a pest's natural enemy into a new area where it does not live naturally. The second strategy is augmentation. This means adding more natural enemies to an area to boost their numbers. Augmentation can be done through inoculative release, where small numbers are released to reproduce and prevent future outbreaks. It can also be done through inundative release, where huge numbers are released to fix an existing problem quickly.

The third strategy is conservation, also known as inoculative release. This involves taking measures to maintain and protect natural enemies that are already present in an environment. To be successful, a biological control agent needs specific traits. It must have the ability to colonize a new area effectively. It also needs temporal persistence, meaning it can survive even when the pest population is low. Finally, it should be an opportunistic forager. This allows the agent to find and exploit pest populations very rapidly.

Humans have used biological control for many centuries. One of the earliest reports comes from a Chinese text called "Nanfang Caomu Zhuang." This book was attributed to the botanist Ji Han, who lived during the Western Jin dynasty. It described how people in Jiaozhi used reddish-yellow ants to protect citrus fruits. These ants were known as huang gan ants. Modern biological control techniques began to emerge more clearly in the 1870s. During this time, entomologists in the United States began redistributing parasitoids to manage crop pests.

History shows several major successes in the field. In 1873, Charles V. Riley made the first international shipment of a control agent. He sent predatory mites to France to fight the grapevine phylloxera. In the late 1880s, the vedalia beetle was moved from Australia to California. This beetle helped control the cottony cushion scale, which was hurting the citrus industry. By the end of 1889, the scale population had already declined significantly.

Other impressive examples show how biocontrol can change landscapes. In Australia, the prickly pear cactus covered over 25 million hectares by 1920. To stop this, the cactus moth was introduced. Between 1926 and 1931, tens of millions of moth eggs were distributed. By 1932, most of the prickly pear had been destroyed. In Zimbabwe, the salvinia weevil helped control the giant salvinia weed. This program achieved 99 percent control of the weed over a two-year period.

Biological control is a vital part of integrated pest management (IPM) programs. However, scientists must be very careful when introducing new species. If a species is introduced without understanding the consequences, it can harm biodiversity. This happens if the agent attacks non-target species that were not meant to be part of the control. Today, new technology is even being used to help. For example, drones are now being introduced to assist with inundative releases of control agents.