You’re worried that they’re killing your plant. And that’s a legitimate concern as these caterpillars will demolish a plant with their hungry appetite.
In this article, we’ll cover these topics:
Common bugs that eat Mandevilla leaves
Signs of caterpillar damage
How to get rid of oleander caterpillars naturally
Home remedies for other Mandevilla pests (spider mites and mealybugs)
How to protect your Mandevilla from bugs
And more
You should have everything you need to know all in one place! That’s my goal.
No one wants to go from site to site for pieces of information, so I wrote this comprehensive article.
If you have questions, or if I left anything out, post a comment below so I’m aware.
Feel free to bookmark this resource so you can easily return to it!
Let’s dive in and protect your plant!
Sections
What’s eating my Mandevilla?
Caterpillars are no stranger to Mandevilla plants- whether they’re oleanders or not!
Mandevilla laxa (AKA Chilean jasmine) is susceptible to a host of pests because of its attractive blooms and multiple color variation.
The obvious reason is to attract pollinators, however, the colors usually also bring many different bugs that munch on its easy-to-target leaves.
Mandevilla grows in hardiness zones 8-11 based on the USDA. These zones are no stranger to caterpillars that eat leaves, such as the looper worm.
Oleander caterpillars are a common bug that you’ll come across munching on the precious leaves.
We’ll cover how you can naturally control this pest to protect your plant.
What’s an oleander caterpillar?
These are the orange caterpillar larvae of the oleander moth or Syntomeida epilais.
They have a voracious appetite and will quickly devour a Mandevilla plant within a few weeks. They feed in nearly any location where oleander plants can be grown, other than California.
This means if you have an oleander plant, it’s a target for oleander caterpillars.
Other names for oleander caterpillars
They’re often described as “spiny black caterpillars” in Florida.
But they have many different aliases.
For the adult moth:
Wasp moth
Polka-dot moth
Uncle Sam moth
Spotted moth
Oleander moth
Blue orange moth
And the caterpillar larvae are often called:
Spiny caterpillars
Polka-dot spiny
Spotted caterpillars
Spotted orange caterpillars
Orange hairy caterpillars
Oleander caterpillar
Do oleander caterpillars eat other plants?
The majority of these spotted orange caterpillars feed on oleander plants, but they’ve been observed to eat on devil’s potato and desert rose plants.
What do they look like?
Oleander caterpillars are prominent on select Chilean jasmine. (By Flex at English Wikipedia, CC BY-SA 3.0.)
This caterpillar is an orange and black pest that has alarming coloration and long black hairs or spines.
They’re often orange with tints of yellow and spotted with black. The spiny hairs are extremely prominent and stick out of the entire body in small clusters of black bristles. The body is noticeably segmented.
Where are they found?
They’re native to the Caribbean from South America to Central America. Florida is a common state that’s plagued with oleander caterpillars and the Keys.
Colder temperatures kill the bug, but they recolonize after the temperatures pick up again the following spring. Thus, they’re prevalent pests. They exist in America anywhere that oleander plants exist, except California.
What do oleander caterpillars turn into?
They turn into moths after they pupate (spin a cocoon). The larvae form is the caterpillar and the adult form is the moth.
After the larvae feed on oleander for some time, they’ll eventually spin a cocoon in a secure place and then emerge as an oleander moth.
Similar to other caterpillars, oleanders leave behind some telltale signs of damage to your plant.
Some of the most common ones are defoliation, jagged leaves, irregular shapes, missing leaves, bare stems, and holes in the plant leaves.
The damage is apparent and easy to spot, so you should take measures before the damage gets exponential.
These pests often hatch together in waves, so you’ll quickly see your Mandevilla leaves disappearing before your eyes.
Since they’re active at night, you don’t notice until the next day. So you need to act quickly if you want to get them off your plant.
They’re vicious and extremely hungry bugs that’ll eat non stop on your leaves until you just have bare stems leftover. You should see some of the damage they’ve done to plants reported by other people online.
Thankfully, they were able to manually remove them and stop the bugs before their Mandevilla was eaten up. This is where you come on to do the same for your plants. Act fast.
Do they bite? Are oleander caterpillars poisonous?
They don’t bite, sting, or transmit disease. But they’re poisonous. (By Cayobo, CC BY-SA 2.0).
Yes, these caterpillars are poisonous.
They can extract the poisonous compounds and glycosides in plant leaves when they eat and then make a poison that they use against predators. Their long black hair and striking coloration signify to potential predators to not mess with them because they’re dangerous.
They don’t bite or sting, but they can leave behind poison trails.
You should never touch a spotted orange caterpillar by hand. They’re dangerous to humans, dogs, and other mammalians. You should never touch them with your bare hands.
What happens if you touch one?
You’ll get a painful rash that’ll become extremely itchy and dry over time. If you touch your eyes after touching one, this can cause eye-watering and pain.
You should always use protective garden gloves and equipment if you want to remove these caterpillars.
Can they harm dogs?
Yes, they’re harmful to dogs. The glycosides they produce affect mammals, which include both humans and dogs.
You can prune these off and toss the leaf into a bucket of soapy water to kill the eggs and unborn larvae.
Or you can scrape them off using a razor if you want to preserve the leaf. This is usually more trouble than it’s worth, so I’d suggest turning off.
Don’t worry- the Mandevilla plant is resilient and will grow back as long as you didn’t let the bugs do too much damage.
How do I get rid of caterpillars on my Mandevilla naturally?
You can eliminate these caterpillars using a variety of home remedies. (By Cayobo, CC BY-SA 2.0.)
Controlling oleander caterpillars can be difficult as they’re a persistent pest.
However, with continued patience and execution of a good treatment plan, you can definitely exterminate them using a few remedies at home.
Here are a few of the most effective means of control.
Remove them by hand
As simple as it seems, you can manually remove the caterpillars and you’ll reduce their numbers.
Mandevilla is an easy plan to inspect, so you shouldn’t have a difficult time spotting caterpillars and taking them off.
Put on a pair of garden gloves and grab a container of soapy water. Just add a few tablespoons of dish soap to a few cups of water. The exact proportions don’t matter, as long as you can see soapy water.
Then start prying apart the Mandevilla branches and leaves and checking them for oleanders.
When you see one, peel it off and toss it into the container. The mixture of soap and water kills caterpillars within a few minutes. Repeat the process until there are no more visible pests.
Note that caterpillars hatch all around the same time after an adult female moth has deposited her eggs. This means that you’ll often get periods of no caterpillars activity.
And then the next day, you’ll have tons of them seemingly out of nowhere. Caterpillars will come in waves, so be aware of that.
Repeat the process as needed. Oleanders are active at night, so you may have to grab a flashlight to catch them more effectively.
Use neem oil
Neem oil can be an effective treatment against most types of caterpillars in general, no matter the plant.
You can make your own neem oil spray at home by getting a bottle of organic oil and adding a few drops to a cup of water. Then pour it into a spray bottle. Spray it onto the Mandevilla leaves, stem, and surface soil.
You should never spray it during the daytime as the sunlight combined with neem can bake the plant. Neem oil does last for a few days because it has a residual effect. Reapply as needed.
Attract bugs that eat oleander caterpillars
Caterpillars are a delicious and nutritious meal for many hungry species such as lizards, mammals, birds, and even other bugs.
There are many caterpillar predators that can help you take care of them. It’s your job to do some research on what native predators you have in your area and find out how to attract some more of them.
Don’t fret. This is easy. Search engines exist. Just think of all the bugs you see in your yard and search for how to attract more of them.
Here are some common predators of oleander caterpillars:
These predators can help reduce the population on your outdoor plants.
Note that many predators that you think SHOULD be able to feed on them actually can’t because of the natural poison they emit. This means most small rodents and birds aren’t capable of eating oleander spotted caterpillars.
Scrape off oleander eggs
One way to stop the oleander life cycle is to scrape off all the eggs every time you check your plant.
Adult moths deposit their eggs on the leaves of Mandevilla plants, which will hatch into oleander caterpillars.
You can spot the eggs quite easily on Mandevilla leaves because of the color contrast. Look for eggs that are white to yellow laid in organized clusters.
They’ll all be together and you’ll see about 12 to 75 eggs on average. They’re pale and less than 1mm in diameter. Check the undersides of the plant leaves, as this is where they’ll usually be hidden.
You can simply remove the entire leaf or scrape the eggs off and dip them in some soapy water. This will kill the caterpillar larvae and stop them from hatching.
Use a pressure washer
You can use a regular garden hose with a spray nozzle or a pressure washer to knock them off your plant.
They don’t have grip under extreme water spray, so you can use any source of strong water streams to get them off your plant.
Of course, they can easily climb back up, so you’ll need to secure the stems of your Chilean jasmine with some barriers.
Sprinkle diatomaceous earth
DE is a natural substance that’s safe for humans and pets that you can use to keep oleander caterpillars off your Mandevilla plants
The trick is to use a ring of DE around the base of the plant- such as forming a circle of powder around the stems.
This way, the caterpillar needs to crawl on the powder to get to the leaves. This can help deter them permanently.
Prune the damaged leaves
The simple removal of Mandevilla leaves can control these pests.
Use a pair of pruners and snip off the foliage where you see holes, tears, and other jagged shapes.
Once snipped, use a container filled with soapy water to catch the leaves. This will kill all the larvae feeding on the leaf.
Be sure to use protective gloves when doing this to shield yourself from the caterpillars.
Freezing caterpillars
You can freeze the caterpillars to kill them also.
Of course, this doesn’t really work with plants. This method should be used to kill off any larvae that you happen to come across from prunings or manual removal.
By tossing them into your freezer, they’ll be frozen and killed. You’ll need at least 24 hours to kill them all off.
This is a germ colony that’s applied directly to the plant. The caterpillars crawl on the Bt which produces a protein that’s lethal to these larvae yet doesn’t kill beneficial bugs.
Bt is also harmless to oleander plants, desert rose, and Chilean jasmine. You can buy Bt from nurseries or hardware stores. Use it as directed by the product label.
Commercial approaches
You should avoid using any chemicals to get rid of caterpillars when possible because of the harmful residues deposited.
Not to mention they’re harmful to the environment in more ways than you can imagine. If you must use a store-bought spray, get something that’s organic or natural and safe for pets.
How to keep caterpillars off Mandevilla plants
Here are some natural remedies to control these pests.
A combination of the techniques listed here can work together to make a very secure and safe plant.
You can do something like this:
Use DE around the stems and soil
Apply neem oil every other week
Do manual pruning every weekend
Spray with soapy water or vinegar every other day
Prune damaged foliage daily
Check for pests daily
Lure natural predators to help control the pest population
These will help you keep the bugs off your plant going forward.
Will Mandevilla grow back after being eaten?
Most Mandevilla plants will sprout new leaves even after being eaten by bugs.
As long as there are no root pests and the plant is receiving a steady source of food, light, and basic plant TLC, new leaves will sprout.
Just don’t let the damage from the caterpillars (or other bugs) prolong or else you’ll just have bare branches.
This is why diatomaceous earth (DE) is useful in the soil to prevent bugs that live in it from eating up the Mandevilla roots. You can sprinkle some around the stem to kill bugs that dare to cross!
How do you get rid of spider mites on a Mandevilla?
Spider mites react to soapy water, so you can make some and spray your plants with the solution. It kills them right away so it’s pretty decent. Vinegar also seems to be effective as a DIY pesticide. Mix it with equal parts of water and spray away.
Lemon or lime juice kills spider mites upon contact. You can squeeze fresh ones or just buy the extra and apply using a spray bottle. Be sure to wash your plant after you spray, as these acidic juices can burn your plant.
You can use anything from a strong stream of water, manual removal, or use a disposable toothbrush.
You can mix and soap and water together to make a mealybug killer and use it on your plant. Essential oils are also a possibility and a favorite of DIYers.
Currently an active researcher in the pest control industry for the past 8 years- with a focus on using natural and organic methods to eliminate pest problems.
I share handy DIY pest techniques I come across here to help out others (and possibly save them from a mental breakdown).
I sprayed my Mandeville plants with the home remedy soap method to get rid of the caterpillars. Now all my leaves are turning yellow. Please help