If the classic children’s book The Very Hungry Caterpillar has taught us anything, it is that caterpillars eat a lot—specifically plants and foliage. However, while this may seem amusing to our children, it can be quite a nightmare for gardeners and farmers. Luckily, there are many ways these insects can be eliminated, although most methods involve poisoning or killing them.
How do you get rid of caterpillars without killing them? If you are trying to get rid of caterpillars in a more humane way, try the following methods:
- Be Proactive with the Garden
- Use a Net to Cover Crops
- Use Cardboard at Plant Base
- Invite Plant-Friendly Insects
- Spray Soap & Water or Pepper Mix
The most common way to eliminate caterpillars without causing damage to plants is spraying bacillus thuringiensis (BT) all over their leaves. However, BT is a flesh-eating bacterium, meaning upon consumption, caterpillars will eventually die. There are plenty of other humane ways to rid the garden of caterpillars.
Understanding Caterpillars & Plants
Caterpillars are the larvae of moths and butterflies, but they first start off as eggs. As soon as they hatch, they emerge incredibly hungry, but for a good reason: they must keep eating to grow and build up enough energy to eventually form their cocoon and emerge as a moth or butterfly.
Why Are Caterpillars Harmful to Plants?
Because caterpillars require a lot of food to thrive, they often navigate and find places that can provide the resources they need. Unfortunately for farmers and gardeners, those places often include gardens.
As a result, many plants are found with a number of holes and chewed leaves, which can hurt their long-term health. In addition, many species of caterpillars like to burrow holes into fully developed vegetables and fruits to devour them from the inside out. To make things worse, caterpillars can leave behind waste and silk as they eat on or in plants, making them inedible for human consumption.
Finally, once caterpillars have established a home in your garden, they can reproduce and eventually spread out across many of your plants you would rather keep unharmed. For these reasons and more, it is always better to remove caterpillars as soon as you notice signs of early infestation.
Good Caterpillars vs. Bad Caterpillars
As you can tell, caterpillars are known to enjoy the unlimited supply of food gardens and farms provide them, including a variety of flowers, fruits, vegetables, and even trees that are available for the taking.
But even though all caterpillars share the love of eating plants, only certain species of caterpillars can prove harmful to your garden. Other species eventually morph into butterflies or moths that turn out to be quite beneficial to plants, and those are the ones you want to keep around.
Caterpillars that Infest Farms & Gardens
So, how do you tell the difference between good caterpillars and bad ones? First, it helps to have an understanding of harmful caterpillar species commonly found on farms and in gardens:
Cabbage loopers often appear pale green, with stripes running down their back. They are one example of caterpillar species that can cause harm to vegetable plants, especially collards, kale, cabbage, lettuce, and other leafy greens they enjoy eating. They can also feed on other vegetables such as lima and snap beans, broccoli and cauliflower, brussels sprouts, radishes, and turnips.
They can cause damage to these plants by simply chewing small to large holes in their leaves, and are known to burrow deep into the heads of cabbages—hence their name.
Cabbage loopers are the larvae of brown and green moths that have silver spots on the wings, so if you start to see these particular moths among your plants, prepare to get rid of a few caterpillars they may be leaving behind!
European Corn Borers
European corn borers (also known as corn earworms) are more likely to appear in late summer or early fall, usually in August or September. They have a pale-yellow appearance with small black or brown spots. As their name suggests, they are notorious for boring holes into stalks and ears of corn. They are also fond of chard, peppers, potatoes, and tomatoes.
Tomato hornworms are quite long compared to other species, often ranging in lengths of three to five inches. They are green in appearance and are recognized by the small horn located on its rear. Tomato hornworms often target tomato, eggplant, potato, and dill plants as sources of food.
These two-inch caterpillars are bright green but are more recognized by the black, yellow-dotted bands that stretch across their backs. They often give off an odor and display orange horns if they feel threatened. Oftentimes they feed on carrots, celery, parsnip, dill, fennel, and parsley.
Tent caterpillars are more commonly found in various trees rather than small plants. They create large silk nests between branches and feed on the tree’s foliage for sustenance. Because these caterpillars reside in trees, for the most part, it is important that you remove their nest in addition to the insects.
Other Common Garden Caterpillars
Other harmful species of caterpillars often found on farms or in gardens include:
- Imported Cabbage Worm – Similarly to cabbage loopers, imported cabbage worms are known to bore into heads of cabbage, while simultaneously turning them to mush.
- Squash Vine Borers – These caterpillars typically go after crops such as cucumbers, pumpkins, squash, and watermelons. They tend to burrow into their vines, which leads to wilting.
- Leaf Curlers – Often found on fruit-bearing trees and vines, leaf curlers (also known as leafrollers) hide within leaves that have been folded or curled up. They are especially attracted to new, tender leaves as a source of food.
- Cutworms – Cutworms are named for their attraction to new shoots and seedlings within a garden or farm.
To learn more about other types of good and bad caterpillars for the garden, check out the Peterson Guide to Caterpillars of North America (click to see on Amazon). It has plenty of information about the different species of these insects not covered here.
How to Tell If You Have a Caterpillar Infestation
Caterpillars use natural camouflage to blend in with their surroundings. Because of this, it is easy for anyone to miss their presence. If you are not sure whether or not you have a caterpillar infestation, here are some signs to look for:
- Caterpillar Eggs – They may be small, but can be distinguishable. First, try looking for nearby moths or butterflies around your plants. If there are any crawling on a plant for a while, chances are they are preparing to lay eggs. Any tiny white, green, yellow, or brown specks they leave behind are the eggs.
- Noticeable Holes – Holes are signs that a caterpillar has helped itself to lunch at the expense of your plants. Most caterpillar-made holes can be found in the leaves or other sections of the plant, usually near the edges.
- Chewed Leaf Edges – Chewed and ragged leaf edges are yet another sign that a caterpillar has started eating parts of your plants. Caterpillars often start eating from the edges of leaves and work their way in.
- Frass – Frass, or caterpillar excrement, has the appearance of pepper grains, and are usually found on foliage nearby feeding caterpillars.
- Rolled Up Leaves – Many caterpillar species like to hide under folded or rolled-up leaves as a form of shelter.
- Leaves Covered in Silk – Some caterpillars cover areas of a plant in silk to serve as their nesting site.
If you notice any or all of the above signs, chances are you have a caterpillar problem on your hands. The remainder of this article will explore the ways in which you can naturally remove them from your garden without causing additional damage to your plant, and safely removing the insects without the need to kill them.
7 Ways to Get Rid of Caterpillars
If you want your plants to be left alone from caterpillars, but want to avoid causing them harm, the following methods are a few humane ways to get rid of these common gardening pests:
1. Be Proactive: Plan Ahead for Your Garden
Of course, prevention is always the best method of ensuring that caterpillars do not reap havoc on your plants. Some proactive ways you can stay ahead of these hungry pests include high-intensity intercropping, keeping your garden healthy, and thoroughly cleaning out plant debris at the end of a season.
High-intensity intercropping involves planting a selection of herbs and spices alongside your usual crops or plants. The herbs help mask the smell of nearby plants that typically attract caterpillars. Some of the most common herbs used in high-intensity intercropping include:
Outside of producing a strong scent that deters caterpillars, you can also harvest fully grown herbs for your personal use throughout the growing season.
Keep Your Garden Healthy
This tip is a given for any gardener who wants their plants to thrive, but it is very important if you want to avoid extending an open invitation to caterpillars. Make sure you use fertilizer or compost regularly to ensure your garden stays healthy throughout the season.
Clean Out Extra Debris After a Growing Season
After the end of a growing season, be sure to remove any garden debris from the area that might serve as a home for future caterpillars.
Many caterpillars overwinter in the soil or garden litter left behind from the previous season, so by removing all old plants for compost, and eliminating overgrown weeds to leave the soil bare, these pests are discouraged from staying throughout the cold season.
2. Use a Net
Another way to protect your crops early on is to set up floating row covers (available on Amazon) or a tiny-meshed net to prevent butterflies and moths from laying eggs atop their leaves. Make sure there is enough room for water and sunlight to get through.
By placing cardboard around the base of your plants, you can discourage certain species of caterpillars—such as cutworms—from interfering with or crawling up the base of the plant to munch on its early stem or leaves.
This method works well during the early stages of a garden when you notice early shoots begin to form. Use cardboard tubes, such as those that remain from an emptied paper towel or toilet paper roll, to surround the plant’s stem and shoots to keep it safe.
Because this process takes some time to do, it is not ideal for large farms but is often recommended for small plants and gardens.
4. Invite Plant-Friendly Insects into the Garden
Certain species of caterpillars can certainly hurt your plants, but do not forget about the beneficial insects, too! Certain insects, such as fireflies, ground and soldier beetles, and tachinid flies, either prey on or parasitize caterpillars and other insects that cause harm, which will discourage any more from entering your garden.
Having other beneficial insects—even those that do not prey on caterpillars—can help reduce their population, by taking over the habitat area. Some of these helpful insects include:
- Praying Mantises
The plus side to having these insects around is that once they have chosen your garden as their home, they do not require interference or regular maintenance–they handle everything else on their own from there!
5. Spray a Soap & Water Mix on Plant
For this, all you need is an organic liquid soap, water, and a spray bottle. Dissolve a small amount of soap into the water inside of the bottle by shaking the mixture, and then mist any affected plants. Make sure to cover both the top surface of leaves, as well as underneath them. Carefully unravel any folded or rolled up leaves and spray these areas, too.
The soap and water mix will not harm the caterpillars or plants, but it will make it quite difficult for the insects to climb and stay on.
6. Spray a Pepper Mix on Plant
Like a soap and water mix, a pepper mix can also deter caterpillars from eating plants.
To create it, start by mixing one tablespoon of dried red pepper flakes, one whole onion, minced, and one teaspoon of organic liquid soap with a gallon of water. After the mixture has been blended thoroughly, allow it to sit for at least 24 hours. Afterward, fill a spray bottle with some of the solution and mist it over the affected plants.
Not only will this mixture prevent caterpillars from daring to climb up the plant, but the strong taste will also prevent them from wanting to take any more bites out from it.
7. Handpick Unwanted Caterpillars
A final tried and true way of eliminating unwanted caterpillars is by picking them off the plants by hand. Make sure that you wear protective gloves before picking off the insects, as some species—such as saddlebacks—can sting or cause rashes on contact.
As you find caterpillars, place them in a bucket filled with a shallow amount of water mixed with organic liquid soap. Check underneath leaves as well as under rolled and folded leaves for stragglers. If you find that some caterpillars are difficult to handpick, spritz them with a bottle of water. They will start wriggling and will make it easier for you to pick them up.
Once you feel you have found them all, or the majority of them, transport the caterpillars in the bucket to a new area that offers a suitable habitat for them, such as an open meadow. Do not relocate the insects to another part of your yard; this will only encourage them to return back to the garden to repopulate.
Naturally, this method can also take quite a bit of time but is most effective if you have a small garden. This is also the least harmful to caterpillars. However, you need to discover the infestation early or you will be frustrated by the amount of time you will spend trying to “rescue” them.
Other Tips for Reducing Caterpillar Infestations
Once you have finally gotten rid of the caterpillars in your garden, it is important to practice methods that ensure they stay out, too. The following are a couple of final tips to remember to avoid having future caterpillar infestations:
- At night, make sure any lights near the garden are turned off; they can attract moths that could potentially lay eggs in the area.
- Be mindful of any specific plants or flowers that can attract butterflies or moths that can produce harmful larvae.
If you want to free your garden or farm from the very hungry caterpillars, try out a few of the above tips. These methods are not only plant-friendly, but they are also caterpillar-friendly, too. Mother Nature will thank you later!