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.
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.