So, you need to get rid of sawflies and their larvae.
These hungry worm-like pests won’t let up anytime soon until they’ve chewed through your leaves and left a veiny skeleton behind.
In this article, we’ll cover:
- How to ID sawflies from bees and wasps
- Signs of common sawfly damage
- Natural ways to get rid of sawfly larvae using DIY techniques
- Sawfly control on rose, oak, pear, and more
- Common species found in the United States
- And more!
You should have a solid foundation and understanding by the end of this article to control, deter, and exterminate sawflies.
If you have any questions, ask!
Bookmark this page for easy reference.
Sound good? Let’s save your leaves from sawflies.
Last updated: 7/2/20.
What’s a sawfly?
A sawfly is in the same family as bees and wasps.
They get their name from their saw-shaped egg “depositor” also known as an ovipositor on females.
These bugs will cut into leaves to lay eggs, which is why you may find partially deposited eggs that stick out from the leaf!
They’re also known as wood wasps.
There are over 8000 species each with their own habitat and characteristics.
Sawflies don’t have a wasp waist, unlike regular bees and wasps which do.
This is the main difference between sawflies and wasps and makes it easy to tell them apart.
What do they look like?
You can easily tell an adult sawfly from wasps and bees because of their stout bodies without a stinger.
They’re actually pretty rare and will hide most of the day, so you’ll likely see more larvae than adults. The female adults lay eggs in “saw” structure, which is where their name comes from.
Adult sawfly appearance
They come in a variety of colors, but the most common species in the US are black and yellow. They have a pair of obvious antennae and giant black beady eyes.
Sawflies also have 6 legs and a long abdomen that’s covered by their neatly folded wings. They measure about 0.1” to .80” on average.
People confuse them over wasps and bees since their appearance is very similar, however, they’re a completely different species.
They’re in the same order (Hymenoptera) which also happens to be the order as ants, bees, and wasps.
Sawfly larvae appearance
The sawfly larvae may be confused with caterpillar and moth larvae, as they all look like worms crawling around on the leaves and stems of plants.
They are worm-like and crawl around like worms and have many different patterns. You’ll often find them crawling around on leaves, especially on the edge.
There can also be outbreaks of sawflies in the summer which can quickly eat up foliage. Larvae often feed together to avoid predators for safety in numbers.
However, you can tell them apart by looking for these common anatomical features:
- Sawflies have six pairs of legs (also known as prolegs)
- Caterpillars have only two to five pairs of legs
- Sawfly legs are harder to see and don’t protrude to the degree that caterpillar or moth larvae do
- Sawfly larvae are hairless (or have very few hairs)
- Caterpillar larvae are hairy
- Sawfly larvae are about 1” at adult size
- Caterpillars can be much lengthier
- Moth larvae have hairy, spiny, or smooth bodies, but are often longer than sawflies
- Sawflies arch their bodies if they feel threatened
Sawfly life cycle
Sawflies have a complete metamorphosis that’s similar to butterflies and moths.
It all starts with an adult female. She deposits her eggs on leaf surfaces by cutting a hole into the leaf and stashing her eggs there.
Some sawflies will seek out specific plants or materials to lay eggs, such as the pine sawfly only using pine wood or bark.
They lay 30-90 eggs on average per female and usually deposit the eggs within the sunlight for faster growth. They also tend to prefer younger leaflets.
Hatching and larvae merge
Within 2-8 weeks, the eggs hatch depending on the environment and temperature. The larvae then begin to feed on the leaves of the host plant and this is where most of the damage is done.
They’ll begin to go through six larval stages that each last a few days to weeks. Within 2-4 months, the larvae will then fall into the soil and begin to pupate.
Pupation and overwintering
This is when you’ll notice many different larvae “worms” crawling around on the soil as they seek a place to spin a cocoon. The larvae may also combine with other nearby sawfly populations to form a larger colony.
The large groups help protect them from predators and they feed during the night. This continues for up to 2 years.
Larvae will form chambers under the soil. Some may spin a cocoon on a leaf surface. Pine sawflies may even dig tunnels.
Adult sawflies emerge
Adults will then emerge after overwintering and the cycle continues. Most have one generation per year, but some may have them less frequently.
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There are also more female sawflies than males.
Signs of sawflies
The easiest way to tell if your plant has sawflies is to look for the larvae.
They emerge from their eggs during the summer months of June or august and feed during this time. You’ll see them crawling around on the leaves during this time.
Depending on the specific plant you have, the appearance and habits of the larvae vary. Some larvae have patterned markings, such as the oak sawfly.
Others such as the rose sawfly have their own patterned green “worm” look that almost looks like a looper caterpillar.
What do sawflies eat?
Adult sawflies eat a variety of things like honeydew, tree sap, plant nectar, pollen, and even other pests. Sawfly larvae eat only leaf matter, and this is where the majority of plant damage comes from.
They have two significant parts of their life cycle and feast on different things.
As larvae, which look similar to a worm or caterpillar, they eat young and tender leaves.
Adults feed on a variety of plants, pollen, nectar, shrub or tree sap, honeydew from whiteflies, and even other bugs.
The most vulnerable plants are trees and shrubs. Sawflies eat coniferous and deciduous trees and shrubs.
There are many different types of sawfly species:
- Dogwood sawfly
- Columbine sawfly
- Grass sawfly
- Dusky birch sawfly
- Rose slug sawfly
- Curled rose sawfly
- Elm sawfly
- Azalea sawfly
- Black-headed ash sawfly
- Dusky birch sawfly
- European pine sawfly
- White pine sawfly
- Larch sawfly
- Yellow-headed sawfly
- Redheaded pine sawfly
- Mountain ash sawfly
- Willow sawfly
- Pear sawfly (AKA pear slug)
- Scarlet oak sawfly
Adults will emerge during the spring and summer after the winter and will feed less on leaf material and more on pollen, nectar, and other bugs.
Larvae will feed exclusively on the plant leaves or needles.
Their damage mainly affects the appearance of trees and shrubs, leaving nothing but skeletal leaves or holes.
Established plants are rarely killed by sawflies unless the population is out of control.
Sawfly damage to plants
Sawflies will damage plants from the “inside out.” This is why they’re also sometimes referred to as leaf miners.
They aren’t dangerous to plants in small numbers, but they rapidly multiply and that’s when the damage they output grows exponentially.
These pests are defensive species and tend to shy away from humans, pets, and predators. When attacked or cornered, they release a nasty scented liquid that repels predators.
If you see one buzzing around, chances are that you have a bunch of unborn eggs somewhere in your yard. They lay eggs in pods and are found across leaf veins or surfaces.
Some species will even inject the egg directly into the leaf and make it hard to spot them. You may see small “thorns” poking out of the leaf (especially around the vein or edges). These could be sawfly eggs that are partially buried under the leaf.
The larvae will consume the plant from the inside of the leaf outwards.
These are the common signs of sawfly damage:
- Holes in the leaves
- Notches forming on the leaf edges
- Skeletonized leaves (only veins remaining)
- Spotty or irregular damage
- Jagged chew patterns
- Random holes all over the leaf surface that are not uniform in shape
Sawflies rarely will be able to kill adult plants, especially trees and shrubs that are established.
However, the damage they do can kill smaller plants like seedlings or leaflets that just sprouted.
Also, this doesn’t mean you shouldn’t do anything if you have them on your plants. Leaving them to consume the leaves will hurt the defense of the plant, which will weaken it and make it susceptible to fungus, diseases, and other predators.
Will sawflies kill plants?
Adult established plants are nearly 100% tolerant of sawfly damage.
However, the foliage won’t. The larvae will eat up the leaves of the plant and leave it barren and wilted. This may then make even established plants unhealthy and susceptible to diseases, stunted growth, or smaller leaves and failed blooms.
Younger plants are much more prone to sawfly damage.
Their young leaflets that are tender and full of plant juice will be eaten up by the larvae- leaving only just the skeletal veiny leaves.
Farmers who grow crops such as wheat can also lose harvest to these larvae, which is what makes them a true pest to deal with.
Since they’re often confused over caterpillars and moths, some people leave them alone thinking that they can’t do much damage.
‘But they’re wrong until they see their leaves being eaten until there’s nothing left!
That’s why you need to act quickly. Factors like the time of year, plant health, shrub or tree type, and the number of larvae you have all are critical.
These are variables you should consider to determine the extent of the sawfly damage.
The first appearance of larvae will vary depending on the temperature conditions, weather, and season. Predict the life cycle. Check for larvae as soon as early summer hits.
Remember that being on top of your plants and knowing what’s going on is key.
Are sawflies harmful to humans?
Sawflies are harmless to humans and pets.
Adults don’t have any stingers. The larvae may use a smelly spray on predators and work in groups, but this is harmless towards humans. You should always use protective gloves, goggles, and other means before attempting to handle them regardless.
They don’t bite, sting, or transmit any known disease.
Sawflies are only harmful to young plants or established plants that are overrun with a huge population. Most people will end up dealing with the larvae which are the most destructive part of their life cycle.
This is when they become most destructive towards plants as they feed on vulnerable leaves.
Sawflies and healthy plants
Sawflies will rarely be able to kill plants that are established, especially large ones. If you keep your shrubs and trees healthy, the larvae must be monitored over time.
But you don’t need to worry about them if you keep the population in check.
A healthy plant doesn’t suffer as much as a young, vulnerable plant. Choose plants that are hardy and resistant to diseases.
Do your basic TLC (fertilizing, feeding, pruning, and watering). Your plant will be able to resist damage from these pests. If your plant already is damaged or diseased, then you need to start a treatment plan for sawflies right away.
Adult sawflies will lay dozens to hundreds of eggs all over your plant leaves.
There’s no predicting how many sawfly larvae you’ll be dealing with as the number varies. While the life cycle for atypical sawfly is short, the number of larvae you have may end up being in the hundreds after they emerge in the summer.
Adult sawflies will deposit eggs all over the veins and edges of leaves. The eggs are noticeable and easily seen unless partially deposited within the leaf as some species practice.
The larvae will then emerge after a short incubation period and begin feeding on the leaves.
This is primarily when most damage occurs. The extent of larvae damage doesn’t compare to how little an adult does.
Nearly all the trouble that farmers or gardeners deal with come directly from the larvae as they solely feed on plant foliage. Adult sawflies have a varied omnivorous diet and can eat other bugs, pollen, and even honeydew.
Thus, adults are nothing to be concerned about. It’s the larvae that you want to control and get rid of.
What do sawfly eggs look like?
Sawfly eggs are visible on the bottom of leaves.
You’ll find them lined up in a row against leaf veins and usually, every egg touches the vein. They may also be visible on the leaf surfaces as black spots that partially protrude.
Some sawflies will lay their eggs along the edges of leaves also. Each egg is white to tan and ovular in shape. They turn darker and more elongated as the larvae are about to hatch, which usually occurs in June.
Where do sawflies lay their eggs?
Sawflies lay their eggs during the springtime on leaf surfaces, veins, and edges.
They aren’t really active creatures, so they don’t move far from their host plant as they fly short distances.
Larvae will hatch and feed from June to August and then drop into the soil to pupate. Pupation means spinning cocoons and then emerging as an adult with wings after the winter. This is also called overwintering.
During their pupae formation, they can’t move and are basically stoic. You can actually remove the cocoons you come across and toss them into a bucket of dish soap.
This will help get rid of a huge sawfly emergence when they evolve. While you can’t get rid of all of them, you can still remove a bunch by hand and kill them off over time.
Do sawflies nest in the ground?
Yes, sawflies will burrow into the plant soil to pupate and spin a cocoon
This is how they stay safe during the winter as they overwinter into adults. This step usually lasts about 2-4 months, but depends on the species, temperature, and environment.
How to get rid of sawflies naturally
Here are some methods you can do at home to get rid of sawflies naturally.
Remember to use a combo of these techniques and see what works best for you. Then scale that method up!
Will soapy water kill sawfly larvae?
Yes, soapy water can be used to kill sawflies.
You can make your own sawfly killer by mixing dish soap and water. Then spray it directly onto the larvae to kill them. This is definitely a fast, cheap, and easy technique to quickly get rid of them.
The only problem is that you need to do it daily to make sure you bring their numbers down.
You can manually pick off the larvae with a pair of tweezers and drop them into a bucket of soap water. This works to get rid of sawfly caterpillars (larvae) or worms.
Cultivate your plants
Basic cultivation of your plants can help deter and repel them without much effort. You should start mulching, pruning, and cultivating in the spring (once early spring and once again late spring).
Then repeat the process again in the fall (early and late fall). This won’t kill the pests, but will help reduce their population by driving out the sawflies that are overwintering.
Spray them off with a garden hose
As simple as it sounds, you can use a strong garden hose with a pressurized nozzle to blast them off.
The stream of water will help reduce their numbers and if you repeat the process daily (such as when you water your roses, dusky birch, or dogwood), you can disturb their environment which will make them less likely to establish and remain around your plants.
Even if you don’t have a hose nozzle, just use your thumb and cover it. There’s no excuse not to do this because it’s so easy and costs you nothing.
Of course, be careful with delicate plants. Aim for any visible sawflies you see, especially foraging larvae and don’t give them any mercy.
Use diatomaceous earth on your plants
Diatomaceous earth can be used as a DIY pest killer and a natural sawfly control technique. DE can kill fungus gnats in potting soil and dirt, snails in planters, and even sawflies found in Christmas trees during the season.
This powdery substance is made from fossils left in mineral deposits and is completely natural, so it’s safe for humans, pets, and plants.
You can sprinkle DE on the soil of the plants you want to protect from the flies, as the larvae will be crawling around on it.
Also, make a ring of DE around the stem to prevent any larvae from crawling back onto the plant after they’ve fallen off. This also helps stop them from migrating between plants as they’ve yet to fly. If they can’t climb up on the plant, this will save the leaves.
This is a clay that you can use as a natural barrier around your plants. It forms a film that acts as a broad spectrum repellent from a variety of bugs- not limited to just sawflies.
Does neem oil kill sawfly larvae?
Neem oil is an effective oil that can kill sawflies, yet doesn’t harm other beneficial bugs like bees. You can buy pure neem oil and mix it with water to dilute it. Use it as directed.
Neem oil has a lasting effect because it’s sticky, especially when mixed with dish soap. You can mix water, neem oil, and dish soap and create a DIY home pest killer that lasts for weeks.
The recipe is 1 liter of water, 12 drops of dish soap, and a few drops of neem oil depending on how concentrated it is. You may want to do some research online to find neem oil recipes.
Once you create it, you’ll want to test it on a small leaf to check if it damages the plant.
Concentrations that are strong burn and harm the plant, so spray some and test it first. Checkback after 3 or 4 days to see if there’s damage. Apply to the whole plant if it seems okay. If you notice damage or burn, reduce the neem oil drops or add more water.
The neem oil will stay on the plant for a few weeks. But you should reapply after heavy rains.
Neem oil can also burn plants because it traps heat. So don’t use it before or during the time when the sun is out and bright. Use it at sunset. Wash off any excess after application. Read up on neem oil safety and always follow the label.
You can easily pick off the bugs by hand and drop them into a container. Get a bucket and fill it up with some dish soap and water to make a soapy solution.
Then get a pair of garden gloves and check your plants.
Find any sawfly larvae and pick them off by hand. Then dunk them into the container. This will instantly kill them because the soap will drown them. This is a natural and safe approach especially if you’re growing organics or natural veggies.
This way, you don’t contaminate your harvest with nasty poisons and residues.
Repeat this process daily until the sawfly larvae are gone. It won’t get rid of it completely, but it will reduce their numbers dramatically.
Vacuum them up
Don’t want to use your hands?
Then get a shop vac or portal vacuum and suck them off your plants! The vacuum cleaner will easily remove any larvae.
You do NOT need to put the nozzle tip up against the leaf to where it makes contact with it.
This will damage fragile plants and you should be careful. If the vacuum is strong enough, it should suck up the sawfly larvae (and adult sawflies) just by placing the nozzle tip close enough to the plant.
The trick is to not touch the plant, but rather suck up the air surrounding the larvae. This will then suck the larvae into the vacuum.
Adults will fly and take off, but if you get close enough, you can suck up sawfly adults also. This is one way to get rid of sawfly larvae without chemicals or poisons.
Shop vacs have both a suck and release feature, which allows you to deposit them into a trash bag or container full of dish soap.
Whatever you do, use common sense and do it safely. Don’t leave the larvae in the bag as they’ll eventually find their way out of the vacuum.
Sawflies have a ton of natural predators that’ll gladly eat them up. The trick is to find out which natural predators are in your area.
You won’t be able to attract predators that aren’t native, because they’ll never show up in the first place! You can get rid of the larvae naturally using the natural food chain.
Thus, check out this list as a reference and do some research to see if you have these predators in your area.
If you do, research how to attract more of them.
These bugs will help keep sawfly populations in check:
- Predatory wasps
- Small animals
Do ladybugs eat sawfly larvae?
Yes, ladybugs can be used as a sawfly control mechanism as they eat the larvae.
Keep in mind that this depends on how large the larvae have already grown and the specific species.
The larvae will emit a liquid to repel predators and often work in groups, so ladybugs may not be an effective measure to take against them.
However, if you have ladybugs native to your area, you can attract ladybugs as a defense predator.
Sawflies on gooseberries
You can use any DIY home remedy to get rid of them, as gooseberry sawflies aren’t anything special.
A combination of neem oil, manual removal, and dish soap sprays should handle the problem.
You can also use Bt to kill them. Bt is a natural microbe that’s lethal to sawflies and organic.
Sawfly larvae on roses (rose slugs)
Sawflies and their larvae tend to be a popular pest for roses. In fact, the rose slug sawfly is aptly named just because it eats up rose bushes.
This particular post has short stiff hairs with green bodies and dark heads. The bristly rose slug will eat up your leaves and leave them in skeletonized tissue.
Even though they’re not truly slugs (similar to the pear slug), they act like one by chewing through the foliage.
You’ll see holes all over your rose plants as they eat up the foliage. You may also notice slowed growth and damaged buds or failed blooms.
You can start to prune and cultivate your roses.
Regularly check for rose slugs and prune off the leaves with noticeable eggs or signs of rose slug damage. You can also pick them off and use soapy water to kill them.
A strong spray with a garden hose can also get rid of them. Also, water in the early daytime so your roses dry throughout the day. You don’t want the excess moisture to rot the plant overnight.
Use a combination of the methods outlined above to get rid of sawfly larvae on your roses. By making some dish soap and your own insecticidal soap this way, you can control what goes into it to ensure a safe and organic rose treatment.
Be sure to wash down your roses after applying any kind of home remedial spray to them. This will delay any harm or harsh chemicals to the plant. Don’t spray it off right away.
Allow 2 hours for the dish soap to kill the larvae first. Then spray it off. This spray will also help keep sawflies off your rose and can be a natural solution depending on the detergent you use.
You can also use neem oil or manual removal. Or attract natural predators for natural sawfly control.
Sawflies in oak
Oak sawflies such as the pine sawfly will damage the leaves of scarlet, black, pin, and white oaks.
They may also dig tunnels or form pupal chambers throughout the oak. These are hard to control and one of the most common sawflies in oak trees, along with pear slug and rose slug.
Oak sawflies are yellow and green and most often found on pin oak. They eat through the epidermis of the leaf and leave the surface undisturbed. So you need to check the underside to see any damage.
They also become less “slimy” over time as they become larger and will have three pairs of true legs and even more prolegs. You’ll find holes all over the leaves and margins slowly disappear.
They can be controlled using bacillus thuringiensis (Bt) just like pear or rose slugs, though to a lesser degree.
Oak sawflies will require a commercial or industrial poison to kill, such as a pyrethroid or carbaryl. Sevin is a popular pest killer that’s based on carbaryl. Use as directed.
Pear slugs, also known as the pear sawfly, is not a real slug but looks like one.
They have a slimy outer layer and will slowly turn into less of a slug over time.
They eat cherries and pears, but also hawthorn, ornamental Prunus, and mountain ash. They’ve also been spotted eating plum trees.
Just like rose slugs or oak slugs, they eat leaves. You’ll find skeletal leaves that result from their feeding habits. You can use dish soap, neem oil, or even a pressurized hose sprayer to get rid of them.
Commercial bug killers that use carbaryl, permethrin or malathion are also effective against pear slugs.
Use the natural methods outlined. Only resort to poisons if they don’t work if you have a huge outbreak of pear slugs.
Here are some other references you may find useful:
- Sawfly – Wikipedia
- “Symphyta” – Sawflies, Horntails, and Wood Wasps
- Sawflies – Horticulture and Home Pest News
Did you get rid of the sawflies on your plants?
By now, you should have a starting knowledge of how to control, repel, and exterminate sawfly larvae. Getting rid of the larvae can help get rid of the adults to prevent future populations.
Plus, that’s where the damage is done. So focus there.
If you have questions for me, leave a comment and I’ll get back to you ASAP.
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Thanks for reading.
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).
Fight nature with nature.