Animals & Insects

There’s a good chance that if you have a beautiful oak tree in your back or front yard, you are not the only one enjoying it. Maintaining the health of your oak tree is always the most important, and sometimes that means getting rid of those unwanted guests, like oakworms!

In truth, oakworms eat the newly sprouted buds on your oak tree, so infestations can severely limit potential tree growth. You can get rid of oakworms on your oak trees by using dish soap, spraying a Bacillus Thuringiensis (BT), or inviting natural predators such as birds to your environment.

Today we’re going to share with you some simple tips on how you can get rid of oakworms on your oak tree and fast! Keep on reading to find out more!

What Are The Worms in My Oak Tree?

First things first, those little worm-like insects are technically caterpillars called oakworms, and they can take over your entire oak tree! 

When the weather starts to get warmer, and everything comes out of its dormant stages, oakworms are one of the first to appear. Oakworms are early spring insects that start causing havoc once it hatches from mid-March to April.

Once these little insects start hatching – they immediately start feeding, and our oak trees may not even get a chance to fully bud if you have an oak worm infestation!

These caterpillars, unlike oak trees, are not a sight to see. They are hairless, with big heads and small yellow bodies, and will turn black when they are an adult – and just like it says in their name – Oakworms love oak trees.  

Oakworm caterpillars are a threat to oak trees because they love the newly sprouted buds. They can eat the entire leaf until the veins are shown – and then go back for more and eat that too. Yikes!

If you happen to see larger black hairless oakworms or smaller yellow to green oakworms, it’s time to act fast to get rid of them.

Oakworms go dormant in the winter months, and that is the best time to take action and get rid of them. If you have an oakworm infestation, there is a chance your oak tree will decline in health – and we don’t suggest taking that chance!

But you may be wondering – why are oakworms in my oak tree to begin with? The answer is quite simple.

Why Are Oakworms in My Oak Tree?

Oak trees provide everything an oakworm needs: safety, shelter, and food. Who could want more?

When in an oak tree – oakworms are situated safely, high up into the air, away from any oakworm predators that are on the ground.

Oak trees also provide the oakworms with an infinite supply of food – and, although oakworms eat the oak tree leaves, the leaves can regenerate.

An oak tree houses the entire life cycle of an oakworm: from egg to larvae, to pupae, and adult. So, once they are there – oakworms are there to stay.

Why Oakworms Are an Issue For Oak Trees

We’ve talked a lot here about preventing oakworms from our oak trees – but we haven’t talked about why oakworms are a threat to our oak trees in the beginning!

Oakworms, at face value, don’t seem like they would do much harm to our oak trees. But the truth is – they do harm without even realizing it.

An oakworm’s whole purpose is to produce and to eat. Once these little creatures produce, the eggs, which can be upwards of 100 eggs a day, hatch into larvae when spring comes and will immediately hatch and start eating.

An oakworm colony can completely eat the entire canopy of your oak tree. The damage is done when the oakworms eat the buds before the tree gets to produce leaves.

If your oak tree doesn’t produce leaves in season, it will not get as many nutrients or as much water as it needs to survive.

And listen, an oakworm or two is not an issue – but when you start seeing branches full of oakworms – it is time to take action – and we’re going to tell you just how to do that!

Simple Tips to Get Rid of Oakworms in Your Oak Tree

What matters the most here is that your oak tree remains in good health – because an unhealthy oak tree can become a huge problem.

Oak trees are taller than life and are usually situated near homes, and an unhealthy oak tree can fall down and cause destruction. So, if your oak tree has oakworms – let’s get rid of them as soon as possible!

Make Your Oak Tree a Slippery Surface

Once you have oakworms in your oak tree, it’s best to start preventing any more from coming or the ones you removed from coming back.

A really easy method to try to keep oakworms away from your oak trees is to create a slippery surface. All it takes is some extra soapy water or some duct tape, or both for extra slip, to give your oak tree a hard-to-crawl-on trunk.

Grab some dish soap and some water and mix the two in a spray bottle. Once your mix is soapy and bubbly, spray it around the trunks of your oak tree and on the branches and leaves, and really soak it on!

If the dish soap and water aren’t enough, you can wrap your trunks in duct tape and spray the slippery soap onto them!

Place Orange Peels Around Your Oak Tree

So, oakworms don’t like the smell of citrus, and they especially don’t like the taste of oranges!

If you have some orange peels, adding them around the soil of your oak tree and at the base is a way to deter oakworms before they even try to get on your trees!

Imagine only eating leaves all day, bland and earthy – and then all of a sudden tasting an orange? It’s not even about the taste, but how shocking would that be?

To scare oakworms away or to make your oak tree undesirable is to add orange peels to the bottom. The oakworms may even think the oranges are the leaves that fell from the tree!

The thing about oakworms is that they don’t just appear, but the eggs were hatched after an oak moth flew/climbed the trunk and parked itself on a branch – so if you initially scare them away, they won’t climb up and lay their eggs.

One of the best preventative measures is to just make your oak tree as undesirable as possible to an oakworm.

Use a Bacillus Thuringiensis (BT) Spray

Using a pesticide known as Bacillus thuringiensis is one of the common ways to get rid of oakworms on your oak tree.

Bacillus thuringiensis is a naturally occurring, organic bacteria that is found in soil. It works as an insecticide when used in spray form and will not harm any nearby trees, plants, or wildlife unless stated on the back of the spray.

Mixing Bacillus Thuringiensis like this one, Monterey BT Oakworm, and Caterpillar in a spray bottle diluted with water and then spraying it directly on the areas that are affected will work as an organic pesticide.

Bacillus Thuringiensis is a great option because it is non-toxic and will not cause harm to the surrounding areas.

You can even purchase Monterey BT Insecticide Ready to Spray, with the spray nozzle already attached. Spraying it directly onto any oakworm infestations, or, as a preventative, after you have removed all the oakworms, will be an amazing way to get rid of them.

This method will deter oakworms from crawling up into the branches and making a home because they won’t physically be able to get there, as they will keep sliding down!

Make a Spicy Oakworm Insecticide

Oakworms hate spicy scents, and a great way to get rid of them is by spraying a garlicky, hot peppery spray to your tree trunks, branches, and leaves!

Mixing garlic, hot pepper, dish soap, oil, and water will make the perfect spicy insecticide. With the dish soap and oil, the spicy smell will linger for a longer period of time, and plus, it’s a two-and-one because the soap will make for a slippery surface.

In a spray bottle, mix all the ingredients, and then spray a generous amount all along your tree.

Not only will this spicy insecticide prevent oakworms from going by your oak tree, but it will prevent many types of critters – flies, caterpillars, beetles, raccoons, rats, birds, opossums, and even deer.

The smell of spice is often too much for an animal or insect to handle. The spicy aroma will overwhelm their senses, making it harder for an oakworm and other critters to find food and safety.

Insects and animals rely on their sense of smell for almost all things, and without it, they wouldn’t be able to function.

Placing smells strategically around your oak tree will help prevent oakworms and a bunch of other unwanted guests.

Plant Lavender Plants Near Your Oak Tree

With the same idea in mind of using scents as a means to get rid of oakworms, another scent you can try is lavender!

Planting lavender plants around your oak will act like an oakworm barrier and will not only look beautiful but will prevent oakworms and other critters from getting too close to your oak tree.

If planting isn’t for you, another great way to incorporate lavender into your plan of action is to use diluted lavender essential oil and soaking cotton balls in it.

After the cotton balls are fully soaked, adding the lavender balls around your oak tree, or hidden in little hollows or in branches, can help keep oakworms and other pests away.

Lavender, although fresh smelling and pleasing to humans, is overpowering for an insect, especially something as tiny as an oakworm or Caterpillar.

It’s interesting because caterpillars can only see the light and dark – they can’t make out images, so their smell is really all that they rely on.

Add Bird Feeders Near Your Oak Tree

One last way that we suggest you try to get rid of oakworms is to introduce some oakworm predators into your oak trees.

A simple way to get rid of oakworms would be to add bird feeders around the branches. Adding feeders will attract birds to the seed, but once the birds get there and see the oakworms, they will choose the oakworms over the seed.

You can add as many or as few feeders as you like, but remember, the more seed, the more birds! And because birds aren’t typically wreaking havoc on your trees, which makes them an easy wildlife animal to introduce to your environment.

Birds will, however, eat all types of seed. So, if you have just planted some grass or flowers, we don’t suggest doing this step until your grass and flower seed start to germinate.

Have A Professional Remove Them Manually

We are sorry to even say this, especially if you are squeamish, but the tried-and-true method of getting rid of oakworms on our oak tree is by physically removing them.

Now, first and foremost. If you attempt this method, it’s totally your call. We recommend contacting a professional first for identification, to make sure that you actually have oakworms caterpillars and not another stinging caterpillar.

Do not touch the caterpillars. Remember, you aren’t a professional and you don’t want to accidentally touch the incorrect caterpillar.

Below is an image of the Anistoa virginiensis (the pinkstriped oakworm) commonly found in the northwest to northeast.

Take a look at Wikipedia’s images and data on Anisota senatoria (the orangestriped oakworm here) commonly found in the north but can also be found in the south as well.

Now, back to removal.

Using gloves and a stick, and only if you are brave enough on your own, pick an oakworm off the tree do identify it. Make sure not to touch it until a professional is able to examine the oakworm.

Picking oakworms up from their bellies with a stick can be a way to get rid of them without harm and without using your fingers!

If your oak tree branches are high up, you may need to get a ladder to do this, and we also suggest bringing a bucket up with you so that you can place the oakworms into the bucket after you pick them for easier, cleaner removal.

If you and a professional determine that you do indeed have oakworms, we suggest spraying an insecticide, like BT, to prevent the oakworms from coming back.

They can cause damage for multiple seasons at a time, so its important to get rid of them before oakworms cause significant damage to your tree.

Other Types of Worms (Caterpillars) in Oak Trees

There are four common oakworms that you may see in your oak tree, and they all leave different signs of their presence in your oak tree.

Tent Caterpillar

A hairy oakworm with a red-brown body is one of the worms that create webs.

The name Tent Caterpillars comes from the fact that they literally make tents for their oakworm colony. Spinning silky webs around branches, Tent Caterpillars build these webs to keep the oakworms in and will help keep them safe from falling from the oak tree’s high heights.

The webs of Tent Caterpillars are detrimental to the health of the oak tree and are unsightly at that. Imagine a ton of Halloween spider webs hanging from your trees in clumps – that’s what these webs look like.

If you notice an abundance of webs forming, wait it out until the winter months, and take action when the tree becomes dormant. Pruning the branches that the webs are on is the way to protect your tree from an infestation to come.

YellowNecked Caterpillar

This yellow and black striped caterpillar – almost resembling a bumblebee but in oakworm form (no thanks), is a big threat to our oak trees.

The YellowNecked Caterpillars like to eat in foliage sections and will eat the entirety of one section of the oak tree and then move on to the next.

If you start to notice sections of your oak tree’s leaves missing, there’s a good chance you have some YellowNecked Caterpillars on the loose!

To prevent more foliage loss, if you notice empty sections, it’s best to find the culprit and act immediately. You can save the oak tree if you act quickly enough and get rid of these caterpillars.

Oak Leafroller

A relatively small caterpillar with a green or brown body and a dark-colored head, Leafroller oakworms are also web-making oakworms, but these guys act a bit differently.

Leafroller caterpillars literally roll the leaves within their webs. They can make a web the size of a branch, and instead of just keeping the oakworms safe, these webs are created so that these worms can eat branch by branch without having to worry about predators or competition eating them or their food.

Leafroller webs can get completely out of hand, and the oakworms can defoliate the entirety of the oak tree.

If you notice large webs that seem almost impossible to make – well, they are not impossible, and you most likely have a Leafroller infestation on your hands – well, technically on your oak tree!

If you’re finding that you have one of these oak caterpillars on your property, check out our guide with simple tips to remove caterpillars on your oak tree.

That’s a Wrap!

If you notice the presence of oakworms on your oak tree – you should act fast to prevent any infestation and to ensure your oak tree’s health.

A few oakworms here and there is not a problem, and honestly, let those little guys eat – but, when they get out of control, your oak trees can be completely covered, your outdoor spaces can become covered in fallen oakworms, and it will be just a complete mess!

To save your oak trees, use some of these simple steps to get rid of the oakworms, and if you’re not sure what to do, always check in with a professional.

To make sure you aren’t confusing oak worm damage with another oak tree affliction, check out our guide on what’s wrong with your oak tree here.

References:

Coffelt, M. A., & Schultz, P. B. (1990). Development of an aesthetic injury level to decrease pesticide use against orange striped oakworm (Lepidoptera: Saturniidae) in an urban pest management project. Journal of Economic Entomology, 83(5), 2044-2049.

Coffelt, M. A., & Schultz, P. B. (1993). Quantification of an aesthetic injury level and threshold for an urban pest management program against orangestriped oakworm (Lepidoptera: Saturniidae). Journal of economic entomology, 86(5), 1512-1515.

Hiychcock, S. W. (1961). Egg parasitism and larval habits of the orange-striped oakworm. Journal of Economic Entomology, 54(3), 502-503.

“Tent Caterpillars – How Do I Get Rid of Tent Caterpillars?” Texas A&M AgriLife Extension Service, 4 Mar. 2019, https://agrilifeextension.tamu.edu/library/gardening/tent-caterpillars/.

Oak Leafroller – Fs.usda.gov. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5347803.pdf. 

As fall comes around and the leaves continue to change, it is a good time to remember that there are more causes than the seasons that could result in your oak tree losing its leaves. Some animals and insects that eat oak tree leaves, so watch out!

Mammals, birds, and insects alike are all to blame for an oak tree’s leaves mysteriously disappearing. Five of the most detrimental animals and insects for oak trees include birds, oak leafrollers, oakworm caterpillars, tent caterpillars, and oak shothole leafminers.

Below, we are going to give you all the information you need to know about what is a healthy part of nature, and when an animal or insect is going too far in harming your tree’s leaves. So, keep on reading, and let’s get to learning!

What Animals Are Attracted to Oak Trees? 

Oak leaves are not the only attractive part of the tree when it comes to food sources. Over 100 species eat acorns, from squirrels and deer to wood ducks and wild turkeys. 

Many mammals are also drawn to an oak tree primarily because of its sheltering properties. On hot days, animals and people alike can find respite from the sun as they enjoy the shade from the oak’s massive canopy. 

On rainy days, though it is not recommended to sit near a tree in a thunderstorm, the many oak leaves help to block the wind and rain. Small animals especially, like raccoons, chipmunks, squirrels, and birds, take advantage of this helpful characteristic. 

Not only are creatures attracted to oaks for the acorns and the wonderful shelter, but they may also come specifically for something else: the leaves.

What Kind of Insects Are Attracted to Oak Leaves?

When it comes to insects and oak leaves, there should be quick action. Many species of moths use these leaves as their primary source of food, but some species of caterpillars and other similar bugs have an even more extreme negative impact on this important part of the oak tree.

Realistically, many more insects than animals eat oak tree leaves, and they are what you will need to watch out for the most.

What Kind of Animals & Insects Eat Oak Leaves?

There are not too many creatures that specifically opt to make a meal of oak tree leaves. Most prefer the fruit or an acorn as their oak tree source of food.

There are a few pests that you should be aware of, some of which are very harmful and some that are not too bad.

It is important to know what to watch for, so let’s talk the animals and insects that eat oak leaves:

●  Birds. Many species of birds feed on both oak leaves and the insects that cause them harm, resulting in a semi-beneficial relationship to the tree overall. Most of the time, birds should not be much cause for concern, even if they do eat a few leaves here and there. 

●  Oak Leafrollers. A very pesky caterpillar, this one has the potential to cause some serious and detrimental issues if not controlled. Luckily, North Americans do not have as much cause for concern at the moment, but being prepared is key.

●  Oakworm Caterpillars. They may be relatively easy to deter but, left untreated, these little critters can cause some serious havoc on oak leaves and, eventually, the trees themselves. 

●  Tent Caterpillars. These creatures chew leaves and spin silk. Sound like an annoying problem? That’s because it is- you don’t want these caterpillars around your oak trees. 

● Oak Shothole Leafminers. These tiny bugs create big problems, and holes in leaves, that only get worse with time.

Clemson University’s Home and Garden Center shows that most threats to oak trees will be seen in the form of disease or insects that attack sap or bark, but the pests that attack oak leaves should not be overlooked.

Birds Eat Oak Leaves

Many of the same birds that eat acorns also eat oak leaves. This includes but is not limited to blue jays, wild turkeys, crows, mallards, woodpeckers, ducks, and more. 

Even more so than opting for a meal of leaves alone, the University of Florida Extension explains that oak leaves are often a casualty of birds trying to get to the insects in the tree, which do happen to feed on the leaves. 

So, if you see any type of bird perched on a limb of live oak, near a cluster of leaves or a pile of Spanish moss, just know that they are there to get a little more than just a tasty salad.

In fact, this is kind of an interesting situation because the birds feeding on so many types of insects that cause significant harm to a tree helps the tree to increase its growth. By consuming so many leaf-chewing insects, birds can eat some leaves and stilldo more good than bad to the tree itself. 

This is a sort of mutualistic relationship in a way. Birds get food, shelter, and some extra snacks while the tree does not have so many insects vying for its precious foliage. 

If you see many birds in your oak tree, remember that they are helping more than they are hurting. There is no real need to worry about these flying friends. 

When it comes to insects, however, that is another story…

Oak Leafroller Eats Oak Leaves

Oak leafrollers, otherwise known as green oak tortrix, are small caterpillars with a green or brown body. Typically, their heads are a bit darker. 

A particularly harmful critter, much more so than any of the birds mentioned above, this is one to watch for. 

Though not a threat yet in North America, this species is widespread in Europe and parts of Africa and Asia. There are a wide variety of suitable hosts all across the North American continent, so this is a creature to keep tabs on. 

Leafrollers spin webs across leaves to turn them into a feeding area that is more condensed and therefore safer. Over time, this can cause an entire tree to lose all of its leaves. 

So, how do you solve this infestation?

If the problem has not developed into a full-blown infestation, you could just take some trimmers like these ClassicPRO Titanium Bypass Pruning Shears to remove the clusters of leaves that have been affected. 

If this does not work, you may need to rely on some sort of bio-pesticide to get the job done for you. Protect U.S. mentions using BT, Bacillus thuringiensis, to treat true infestations as they occur.

As this is not an issue in North America quite yet, we’ll leave this one at that for now and hope that you won’t need to reference this section unless you are based in a location that is home to these pests.

Oakworm Caterpillars Love Oak

Similar to the oak leafroller, this caterpillar has a body that begins as a greenish-yellow color but this creeping creature gets darker with age.

Between spring and summertime, these critters could completely defoliate a tree. Instead of spinning silk to cluster the leaves, they tend to munch directly on them until they are down to the veins. 

You’ll want to deter these pests quite early on to ensure that they do not overrun your tree entirely. This can be done by using the BT that we talked about in the last section. Read more about this here.

Something like this Garden Safe BT Worm and Caterpillar Killer can help. This product is intended for organic gardening and boasts that it will not harm beneficial insects or animals if used as directed.

You simply mix the product with water, as directed, and spray it on. You’ll need a ladder most likely, but that is a small step to curb a big problem!

If your tree is young and it is a manageable task, you can easily pick individual caterpillars directly off of the leaves. This is recommended only if the process of buying BT and using it would take longer than hand-picking caterpillars.

You can learn more about keeping oakworms off your oak tree here.

Oak Trees Are Feasted On By Tent Caterpillars

Thanks to the University of Kentucky College of Agriculture, we know that tent caterpillar eggs are laid in clusters of 100 to 300. Now that is a LOT of potential pests coming to destroy your beautiful oak leaves. 

With a reddish-brown color and hairy body, this little pest can cause more damage than one might expect. While the first sign of infestation may be thinning crowns, another indicator is the constant dropping of caterpillar waste. 

Not only is this a messy, annoying dilemma, but these particular caterpillars have multiple methods of destroying your oak leaves. Along with weaving strands of silk that add a rather unseemly appearance to the overall look of the tree, these critters will chew right through your oak leaves. 

As the young caterpillars start working their chaos as buds begin to break in the spring, you can try to take a preventive step by either cutting branches in later winter or tree banding in early spring before the infestation can take hold. 

What is tree banding, you may ask?

Basically, you can wrap your tree in a sort of adhesive that is both environmentally friendly and incredibly effective at catching bugs of all kinds. 

This Catchmaster Tree Banding Insect Adhesive Barrier is both easy to use and yields great results. The downside to this product is that it can harm non-target insects and may affect birds, squirrels, and other tree-dwelling critters. You can minimize the risk by putting chickenwire fence over the substance.

Oak Shothole Leafminers Eat Oak

These pests are particularly bothersome because they do not just eat the leaves. Instead, the adult females begin by puncturing into them to consume their sap. This leads to holes forming and expanding as the insects continue to feed and the leaves grow with the season. 

As blotches expand, the leaves weaken and offer up an even more vulnerable area for consumption both by these oak shothole leafminers and other insects that are looking for an easy meal.

Instead of birds or caterpillars, this creature is a small fly that you’ll want to be on the lookout for. 

Unfortunately, there is not much of a solution for these pests, so we want to remind you of ways you can at least maintain control when it comes to their pesky peers.

Keeping Your Oak Leaves Safe From Animals & Insects

There are plenty of methods to help keep critters from eating your oak leaves.

Oklahoma State University tells us that livestock of any kind are much more likely to eat live, green leaves than they are to opt for a snack of dried and/or fallen ones. 

Here are a few methods to keep animals from feasting too frequently on your tree:

Trim Your Leaves If Needed

Remember that by catching the infestation early, you can save a lot of time, stress, and money. This is only going to be successful if there are not already too many insects causing the same sort of problem.

If you see certain insects on your tree and are not sure how bad things are, reach out to a local professional for help.

Use BT to Control Larger Infestations

Has your tree become overrun with pests that are eating, or otherwise destroying, your oak tree leaves? 

Using BT to spray should not cause harm to any beneficial insects, but will help take care of those that are attacking your oak’s foliage. 

Call a Professional

We mentioned it above and we’ll say it again here. If you are not sure how to handle a problem, cannot quite tell how bad it is, or just feel generally overwhelmed, leave it to the professionals!

This is a good way to ensure that the problem will not accidentally go unresolved, and will give you peace of mind from the security of knowing that someone is helping you get this issue under control.

Okay, It’s Time For Us To Leave!

Bad pun? Maybe. Good information? We certainly hope so!

Oak trees are wonderful organisms that do so much for the environment and the critters around them, but it’s good to be aware of those that might do your tree harm.

While oaks are extremely resilient, even they have their limits.

It’s okay to let birds eat leaves once in a while as they work to help you control the tree’s insect population, but this is not always something that you can rely on. While there is a semi-mutualistic relationship there, not every tree is going to draw in birds. 

Often, insects will try to overrun your tree so being a step (or two) ahead is important.

Remember, this article is not a completely comprehensive list of all the pests that may attack and consume your oak leaves, but it does include the most harmful ones. There are other species of caterpillars and flies that will have similar impacts. 

While we know it is not feasible to observe all of the leaves on your tree, especially when it is mature and towering over you and your home, ideally, this will help you feel prepared if you do stumble upon the realization that you have a problem.

We hope that this article helped you to feel more informed about the animals and insects that may feed off of your tree, as well as how to keep them at bay. 

Until next time, thanks for reading.

References

Marquis, R. J., & Whelan, C. J. (1994). Insectivorous birds increase growth of white oak through consumption of leaf‐chewing insects. Ecology, 75(7), 2007-2014.

McManus, Michael L.; Liebhold, Andrew M., eds. Proceedings: Ecology, Survey and Management of Forest Insects; 2002 September 1-5

Rubtsov, V. V. (1983). Mathematical model for development of leaf-eating insects (Oakleaf roller taken as an example). Ecological Modelling, 18(3-4), 269-289.