Biological Pest Control: What Works and What Failed Miserably

Written by Chem-Wise on . Posted in Blog

In 1962, Rachel Carson published “Silent Spring,” a book about the harmful effects of pesticides on the environment. Carson’s book effectively launched the modern environmentalist movement and changed our nation’s policies on the use of pesticides, especially those containing the chemical DDT.

Pest control today is much safer than it was during the ’60s, and Chem-Wise Ecological Pest Management takes our responsibility to the earth seriously. However, today’s methods are the results of a lot of experiments, some of which did not turn out.

Biological pest control, or using natural forces like predators and parasites to keep pest populations low, is one of those alternatives with mixed results. Keep reading to learn which methods have proved successful and which haven’t.

Biological Pest Control That Works

Some biological pest control methods are older than human memory, and some are recent developments. You’ll find some from both categories in this list.

1. Cats

Most people today keep cats as pets, and cats have been domesticated since possibly 8,000 BCE. However, cats are often kept as pest control instead of as companions. Domestic cats in the United States kill about 1.4 to 3.7 billion birds and 6.9 to 20.7 billion mammals (primarily rodents like mice and rats) every year.

2. Dogs

Similarly to cats, many dogs were bred to hunt rodents. Most terrier breeds are natural mousers, such as the rat terrier, dachshund, and Yorkshire terrier. Their small size and high energy help them chase and fit into tight places when on the hunt.

We usually treat these dogs as companions now instead of workers. However, they still have natural instincts for chasing small prey. If you have one of these dogs, you’re probably familiar with how much they want to chase balls or dig-or chase any rabbit, mouse, or gopher that they might come across. If you also own another pet like a hamster or a gerbil, you probably have to keep the two pets apart.

3. Ladybugs

Aphids are tiny bugs that consume leaves. If an infestation develops, an entire crop in a garden or a farm can be decimated. Ladybugs offer a natural solution: ladybugs and their larvae feed on aphids, caterpillars, scale insects, and mites. Some farmers have bought live ladybugs to release into their fields to cut down the pest population.

Another way to take advantage of ladybugs and similar insects is to encourage their native populations instead of simply importing them. In England, researchers found bugs that eat aphids living in grass by the sides of the farmers’ fields. To encourage the aphid predators, the farmers planted those grasses in patches throughout the fields, allowing the bugs more places to live and ultimately reducing the aphid population.

4. Cactus Moths

One of the issues with globalization is the rise of invasive species. If a plant or an animal travels to another part of the world where it does not have natural predators, that species’ population can explode. One example of this is the prickly pear cactus in Australia-the plant was introduced as an ornamental shrub for people’s gardens, but it quickly became a weed.

In this case, the solution was to bring the cactus’s parasites over to Australia as well. To stop the spread of the cactus, scientists brought over the cactus moth, among other bugs. These parasites feed on the cactus, weakening and even killing it.

Biological Pest Control That Failed

Some biological pest control measures didn’t work, and some made things even worse. These two methods were failures.

1. Mongooses

The mongoose is native to Asia and preys on small animals like rodents and birds. In 1883, Hawaiian plantation owners introduced mongooses to their fields in an effort to keep the rat population down.

In theory, this should have worked. However, unlike current methods of biological pest control that take into account the entire environment, this attempt was short sighted. Mongooses don’t just eat rats-they eat whatever they can get. As a result, they have aggressively picked off Hawaii’s bird population without doing much damage to the rodents. They are considered an invasive species and a nuisance today.

2. Cane Toads

The cane toad is another classic example of early failed biological pest control. In 1935, the Bureau of Sugar Experiment Stations brought the toad to Australia to control the local beetle population. The beetles, though native to Australia, threatened sugar cane crops, and the South American cane toad looked like a good solution.

Instead, no evidence exists that shows that the toads have helped with the beetles. But they multiply quickly and are still spreading over Australia. Unfortunately, they can carry diseases that affect native animals around them, making them an enormous threat to Australia’s ecosystem.


Some biological pest control methods work, and some don’t. However, you don’t have to get a cat if you’re worried about mice-call Chem-Wise Ecological Pest Management. We can help you find a low-impact, quick pest control method right for your family. Contact us to get your pest problem solved.