How To Get Rid Of Caterpillars On Ferns

Do you have ferns inside or decorating your landscape? In any location, it is annoying when they are affected by pests. Caterpillars are a common pest we see impacting these plants. This article will answer how you can get rid of caterpillars on your ferns. 

There are a variety of ways to rid your ferns of caterpillars. These methods include:

  • Insecticides
  • Manual plucking 
  • Introducing beneficial insects
  • Physical barriers

We will go on to explain what each method of caterpillar removal entails. Keep reading as we discuss symptoms that your ferns are under stress from caterpillars and how to prevent caterpillar infestations in the future. 

Detailed photo of a fern leaf, How To Get Rid Of Caterpillars On Ferns

Getting Rid Of Caterpillars On Your Ferns

Ferns, or Polypodiophyta, are made up of complex leaves that shower their surroundings with a lush green look. Once established, these plants require little maintenance and are typically resistant to pests. 

However, there is a risk that your plant will suffer from a caterpillar infestation. The best way to treat caterpillar infestations is by preventing them, but if you find your ferns already affected, it is time to seek some solutions. 

A Netelia producta waiting for a caterpillar

Let's take a closer look at how to rid your ferns of caterpillars. 


Caterpillars may look like worms, but they are classified as insects.  Therefore, one way of getting rid of caterpillars that you find on your ferns is by utilizing an insecticide.

Microbial insecticides will help you tackle your caterpillar problem without impacting the other, not harmful insects, around your plant. Many other insects and wildlife benefit your fern, making it important to keep them safe. 

When searching for an insecticide for your ferns, you want to find one that includes ingredients such as spinosad, neem oil, pyrethrin, or azadirachtin. Additionally, there is an insecticide specifically for caterpillars on ferns called Bacillus thuringiensis [B.t]

B.t is found in the gut of caterpillars and works as an environmentally friendly insecticide. The specificity of this product means little to no harm to other insects, wildlife, or humans around the ferns. 

Amazon offers B.t here.

Manual Plucking

Manually removing caterpillars from your ferns is a great option as well. If you notice a caterpillar on one of your leaves, pluck it off, and place it in a bucket of soapy water. You should check your leaves daily for these pests, as well as for their eggs. 

Removing these insects by hand can help decrease the need for chemical intervention. Additionally, you can use water to flush or wash away unseen eggs from your leaves. This will be enough to get your infestation under control in some cases. 

In more severe instances, you may need to add in the help of neem oil or other organic insecticides. Additionally, neem oil works as a fungicide too. These characteristics help resolve insect issues and underlying diseases in your plants. 

You can find a neem oil spray here on Amazon.

Read more on our blog post, 

Can Neem Oil Kill Leaf Miners?

Introducing Beneficial Insects

If you want to avoid adding insecticides and oils to your garden, you can try utilizing beneficial insects. Parasitic wasps are stingless insects that help combat other harmful insects among your plants. 

Caterpillar eggs on a leaf of a fern

Specific parasitic wasps, including Cotesia congregata and Hyposoter exigua, actually target caterpillars. The caterpillar's body becomes the home for the eggs of these wasps, and they become a feeding station that eventually dies off. 

These wasps are small and sometimes barely noticeable. You can tell they are taking over your caterpillar population when you notice the caterpillars taking on a mummified look. 

Additionally, as the larvae of the wasps' hatch, the caterpillars will appear to have rice grains attached to them. 

A caterpillar crawling on the fern

You can attract parasitic wasps to your plants by planting certain herbs and flowers. For example, fennel, dill, and cilantro contain pollen that these wasps feed on. There is the option of buying parasitic wasps to release in your garden. 

Physical Barriers

Placing physical barriers at the base or around your ferns is another non-invasive method for repelling caterpillars. Try placing tin foil or cardboard at the base of your ferns after removing any debris hiding caterpillar eggs. 

Furthermore, you can utilize insect barrier fabrics to cover your plants. If you plan to use these covers, it is essential that all caterpillars and eggs get removed from your plants first. Placing a cover with insects still on your plant protects the insects. 

What Kind Of Caterpillars Affect Ferns?

There are a variety of caterpillars that can affect your garden, but there is a specific one that is troublesome to ferns. The Florida fern caterpillar (Callopistria floridensis) is not influenced by the phytoecdysone compounds on ferns that typically repel insects. 

A caterpillar eating away leaf

Originating in Florida and other tropical areas, ferns in warmer climates are more susceptible to this caterpillar. However, the Florida fern caterpillar has moved farther north and into many greenhouses despite the location. 

This caterpillar ranges in color from green to dark brown and has light-colored markings. They typically feed on Kimberly Queen or Boston ferns. However, other species of ferns can be attacked by these insects. 

The Florida fern caterpillar grows to about 1.5 inches long and eventually becomes a moth. These pests are resistant to many types of insecticides, making it essential to pick the correct method for removing them from your ferns. 

Signs That Your Fern Is Affected By Caterpillars

Many insects are found in your garden, so how do you know you are dealing with caterpillars? With any garden pest, you want to see what you are conquering before moving forward with prevention and treatments. 

Once caterpillars become adults, they are pretty obvious to point out. Long, multicolored, worm-like creatures can be found on your leaves. However, their eggs aren't as easy to spot and are the first step in your infestation. 

A black caterpillar lying on a small leaf

Signs that your ferns are being affected by caterpillars include browning leaves, leaves with holes or missing sections, and stripped foliage. 

The butterfly or moth form of these caterpillars are the ones who lay the eggs. You may be able to spot eggs by thoroughly looking over the leaves of your ferns, including the underside. 

These eggs are initially white or yellow and will darken as they mature. Furthermore, eggs can typically be found in clusters. Look at both your leaves and any debris at the base of your plant to spot eggs. 

Caterpillar eggs on the leaf

Caterpillar Prevention 

If you are dealing with a caterpillar infestation or have in the past, you probably want to know how to protect your plants in the future. As we mentioned, the best way to treat caterpillars is to prevent them in the first place. 

Even newly purchased ferns run the risk of traveling with caterpillar eggs. To prevent an infestation, spray every new fern with B.t when it gets home. You can spray your ferns every year in June with B.t to prevent new caterpillars from hatching. 

B.t is a microbial insecticide and is considered very safe. Spraying every year comes with little to no risk and extensive benefits since it specifically tackles caterpillars on your ferns. 

Gardener spraying his fern plant

Additionally, keep up with regular pruning and removing any dead plant matter. This takes away locations where eggs are likely to hide. You can use some of the methods we talked about for curing infestations to prevent them too. 

Physical barriers can be set in place at any time in your garden. Utilizing cardboard, tinfoil, and covers for your plants can stop the chances of infestations altogether.

Creating ideal conditions to attract beneficial insects into your garden can be part of your plant planning. You have less to worry about if you create an environment that already houses species such as the parasitic wasps before planting ferns. 

Read more on our blog post, 

Does Rain Wash Away Pesticides?

In Summary

Detailed photo of a fern leaf

You can choose one of these methods to remove caterpillars from your ferns or utilize a combination of them for the best results. We hope you found this article helpful for managing caterpillars on your plants. 

Are you looking for more information about caring for your ferns? Have a look through our blog post, 

Do Ferns Need Drainage [And How Much Should You Water Them?]

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