Despite belonging to the same order as bees, sawflies are far from beneficial. Instead, sawflies are pests that can potentially cause a lot of damage depending on the species.
There are 7,000 species of sawflies, with a variety of hosts. This article seeks to shed light on these pests and explore effective treatment methods.
What Are Sawflies?
They are a group of insects characterized by a saw-like ovipositor, which explains the name. The 7,000 different species are spread across seven different families, which makes the sawflies a very diverse bunch.
However, all these families belong to the vast superfamily Tenthredinoidea.
Sawflies are often easy to mistake for bees, wasps, and hornets and belong to the same order as the – order Hymenoptera.
They are also referred to as “primitive wasps.” Both adult and larval sawflies are pests, though the extent of damage varies from one species to another.
Types of sawflies
1. Elm Sawfly
The elm sawfly stands out, especially because its larva is one of the largest sawfly caterpillars in North America.
If you find a metallic blue fly-like bug with a striped abdomen, it might be an elm sawfly.
These insects are notorious for defoliating elm and willow trees, though they sometimes infest boxelder, apple, birch, maple, and other tree species.
Female elm sawflies use their saw-like ovipositors to cut open the leaves of host plants and lay eggs.
2. Rose sawfly
If you find sawfly larvae on roses, it’s likely the larvae of rose sawflies. Also known as the rose slug sawfly, the adult looks like a black fly with a yellow abdomen.
It’s mostly their larvae that cause damage, feeding on the soft tissues of rose shrub leaves and exposing the hard tissues inside.
This skeletonization process badly affects the aesthetic value of the rose shrubs by causing the leaves to turn brown and dry.
3. Pine sawfly
There are several species of pine sawflies out there, among which the European pine sawfly is the most abundant species in North America.
Adult pine sawflies have black heads and bodies and are dotted with yellow and white spots.
Some species of pine sawflies give birth to several generations per year, and their larvae are particularly devastating.
Although they mostly defoliate the crown and the upper part of trees, a pine sawfly infestation can sometimes result in complete defoliation too.
Defoliation caused after the formation of the winter buds can result in the death of branches or even the whole tree.
4. Dogwood sawfly
A black fly with a yellow abdomen, dogwood sawflies closely resemble wasps. As their name suggests, dogwood plants are their most preferred host species.
The adults usually emerge around May to July. Female dogwood flies use their ovipositor to insert up to 100 eggs in a leaf, usually lining them across entire leaves along the veins.
Leaves with dogwood sawfly eggs are easy to identify, as each egg causes a tiny brown bump to appear.
Their larvae can be a huge problem because matured caterpillars of this species tend to bore into softwood, including various lawn furniture.
Interestingly, the larvae of dogwood sawfly take up several appearances, colors, and textures during the molting stages.
5. Birch sawfly
Growing up to almost an inch in length, these large sawflies lay their eggs under the bark of birch trees.
Once again, the saw-shaped ovipositor turns out to be handy. As with all the other pests of this species, the larvae feed on their host plants.
Thankfully, birch sawflies or their larvae don’t cause a lot of damage or defoliation on birch trees.
The effects are usually only short-lasting, though young birch plants are more vulnerable to damage.
6. Raspberry sawfly
The raspberry sawfly is an agricultural pest notorious for feeding on raspberry, loganberry, gooseberry, and blackberry.
Raspberry plants are their most common hosts but can usually survive sawfly infestations without much issue.
In most cases, raspberry sawflies only cause small holes in the leaves. Heavy infestations, however, can result in the leaves getting completely skeletonized.
Adult raspberry sawflies look like stout black wasps, while the larvae are a light green shade, very similar to the leaves they infest.
Where Do They Live?
Sawflies are very common in the US, and you can find them in every state.
Besides other North American countries like Canada and Mexico, these pests are also abundant in Japan and Europe.
Sawflies mostly reside in the temperate zones in the Northern hemisphere.
While one can still find some species of sawflies in African forests, they’re scarce in Australia and absent in New Zealand.
As for their preferred habitat, most of them have specific host plant species. As you may have noticed already, the sawfly species are usually named after the plants they prefer to feed on.
What Do They Eat?
Adult sawflies usually feed on pollen and nectar from flowers, but leaves are often a part of their diet too. Besides, they’re also insect predators and may prey on ants.
It’s the larvae of sawflies that cause the most damage due to their feeding habit. These caterpillars feed on plant tissue, which is why they cause extensive damage to leaves.
Besides, they also have strong mouthparts that allow them to pierce the bark tunnels and suck out tree sap.
Although most sawflies have specific host plants, some are relatively more generalist and cause a lot of damage to garden plants.
What is the Lifecycle of sawflies?
Most species of sawflies have a very short lifespan and die within about six months of hatching. They spend most of this time as larvae and get to spend only a week or two as adults.
However, many sawfly species in Minnesota live up to a year. They have four distinct life stages, like most members of the insect world.
Egg
Their eggs are inserted into plant leaves and petioles and show up as yellow and brown spots on the surface.
As they develop, they grow in size and often protrude through the surface.
Depending on the weather and the species, the time taken for them to hatch ranges from two to eight weeks.
Larvae
The larvae of sawflies are commonly grouped as caterpillars due to the similarities in their appearance and behavior.
Sawfly larvae usually have black spots all over them and move around in groups. When disturbed, all of them tend to rear back their heads together.
This is a key identifying characteristic that can help you distinguish sawfly larvae from other caterpillars.
The larval stage lasts two to four months and comprises six instars.
You might not notice them until they’ve reached the final instar. This is when they start eating large chunks of leaf tissue.
Pupae
While some species of sawfly larvae pupate in the soil, others spin cocoons attached to host plant leaves.
Sawflies take longer to pupate than most common insect species, and this stage may last a few months.
Adults
Finally, the adults emerge and live for up to a couple of weeks. Some sawfly species have longer lifespans and can live for more than a year.
Where Do They Lay Eggs?
Adult female sawflies usually use their ovipositors to insert eggs in plant leaves and petioles.
The eggs may be laid singly, along leaf veins, or in clusters of 30 to 90 eggs, known as pods or rafts.
Some species of sawflies glue their eggs to the surface rather than inserting them into the plant tissue.
Do They Bite or Sting?
Sawflies don’t usually pose a direct threat to humans as they cannot bite or sting.
Despite their similarity to wasps, they do not have stingers, and their saw-like ovipositors aren’t as good weapons.
For this reason, they’re also commonly known as “stingless wasps.”
Are They Poisonous or Venomous?
Sawfly larvae can secrete a distasteful and irritating liquid in self-defense to ward off predators.
If you end up agitating them or making them feel threatened, they might squirt it on your skin or, worse, into your eyes.
Are They Harmful to Humans as Pests?
While not every sawfly species are equally harmful, many of them are major. Sawfly larvae can cause extensive damage to host plants by defoliating them and skeletonizing the leaves.
Heavy sawfly infestations can also result in the death of the host plant or tree.
Thankfully, there’s only one type of sawfly known to attack vegetable crops, and it only feeds on sweet potatoes.
Can They Come Inside Homes?
Sawflies don’t usually get indoors, and most of their preferred hosts aren’t houseplants. However, they might get in through open windows or doors.
Especially if there are trees around your home, there’s a chance that sawflies or sawfly larvae infesting them might fall inside.
What Are Sawflies Attracted To?
Naturally, sawflies are primarily attracted to their preferred host plants. While Both trees and shrubs are vulnerable to various sawfly species.
If you have any potential host plants in your garden, you should watch out for sawflies in spring.
How To Get Rid of Sawflies?
Healthy and mature deciduous plants can usually survive sawfly infestations for a season.
Even if they get defoliated during a severe infestation, they can regrow the leaves.
However, even if a sawfly infestation doesn’t cause any lasting damage to your garden, sawfly damage can greatly lower the aesthetic appeal.
Effective ways to get rid of sawflies include:
Manual removal
If there’s just a small number of sawflies, you can remove them manually and kill them by putting them in a bucket of soapy water.
Spraying water
Simply spraying the infested plants with a high-pressure jet of water to knock off the pests should work too. However, take care not to damage delicate plants.
Natural predators
Attracting natural predators to your garden is a great way to keep pest populations under control. Parasitic wasps can help you get rid of sawfly larvae.
Low-impact insecticides
Before using chemical insecticides, try out low-impact options. Horticultural oils and insecticidal soaps are effective against young larvae and have minimal impact on beneficial species.
You may also use Spinosad and Azadirachtin for residual treatment.
Chemical insecticides
If the other methods fail to bear fruit or you need quick results, you may have to resort to chemical insecticides.
A single treatment of contact residual insecticides like bifenthrin, permethrin, or carbaryl is usually enough.
Alternatively, you may use systematic insecticides that transport through the plant tissues and kill larvae feeding on the leaves or cones.
Frequently Asked Questions
Can sawflies hurt you?
When threatened or aggravated, sawflies secrete an irritable liquid during the larval stage. Apart from this, they aren’t capable of hurting you.
Sawflies can’t bite humans, and unlike wasps, they lack stingers. As long as you don’t mishandle sawfly larvae, you usually need not worry about getting hurt.
Should I get rid of sawfly?
While sawflies are pests, you don’t always need to get rid of them. As long as your plants remain healthy and strong, they can usually withstand and survive sawflies.
However, if it’s a large infestation or the sawfly species is known to cause heavy damage, you should work on eliminating them.
What do sawfly larvae grow into?
Sawfly larvae grow into adult sawflies – insects belonging to the same order as wasps, ants, and bees. While some sawflies look like flies, many species closely resemble wasps.
You are more likely to come across sawfly larvae than adult sawflies, as they live for a very short period as adults.
Is a sawfly a wasp?
Although sawflies are often mistaken as wasps or known as stingless wasps, they’re a completely different group of insects.
Unlike wasps, sawflies don’t have stingers – they have a saw-like ovipositor instead that they use to insert eggs into plant tissue.
Wrap Up
Sawfly identification can be a little difficult due to the similarities they share with other insects. Many sawfly species are Batesian mimics and replicate the behavior of wasps to avoid predators.
However, it’s the larvae that you need to get rid of, and hopefully, this article has been helpful in this regard.
Reader Emails
Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.
Letter 1 – Dogwood Sawfly
Hello bug people,
I’ve had a great time looking at your site and your link to Bug Guide, but I didn’t find a match for these guys that have devoured my red twig dogwood seemingly overnight! It is September 15 in Ionia, NY—-that’s way upstate, south of Rochester and northwest of Canandaigua Lake. Most of them are the white ones, but a few are the black with white stripes. In the 18 years we’ve lived here, nothing has ever eaten this bush. Do you know what they are? And are they two instars of the same caterpillar. Are they good or bad? Thanksverymuchly,
Millie Sigle
Hi Millie,
You will never find your fascinating creatures on a caterpillar page unless they have been misidentified. These are actually Dogwood Sawflies, Macremphytus tarsatus. When we saw your subject line, we thought you might be sending us an image of the Cimbex Sawfly, but we were nicely surprised as this is a new species for our site. According to BugGuide: “Young larvae are covered with a powdery white waxy coating. Mature larvae are yellow beneath with black spots or cross-stripes above.” The Natural Land Trust website has a nice page devoted to the Dogwood Sawfly. Sawflies are related to wasps.
Letter 2 – Sawfly Metamorphosis
Hello,
We really enjoy your site, it’s a great resource. My son and I have been looking at some caterpillars feeding on our Red Currant in Edmonton Alberta Canada.
They are voracious feeders, here are some pictures of the various stages from egg to larvae and adult.
We managed to grow some larvae to the adult stage which made the identification much easier. Would you agree that this is Nematus ribesii – Goosberry Sawfly?
John and Andrew Simon
Dear John and Andrew,
First, we want to praise you for your incredibly excellent documentation of this Sawfly Metamorphosis. What patience and diligence you have. We don’t disagree with your identification based on larval images found on the Down Garden Services website, but a real expert might have a definitive identification. A suspect adult image we located does not match your adult. Thanks ever so much for your contribution of, if not the metamorphosis of the Gooseberry Sawfly, Nematus ribesii, at least a closely related species.
Letter 3 – Striped Alder Sawfly
Found thousands and thousands of these caterpillars infesting a few Alder trees… they are everywhere! Haven’t seen any tents and the trees are now completely leafless. They are quite small, less than an inch in length. Have looked online to identify them, but no luck aside from the fact that I believe they are feeders! Any idea what kind they are?
Amelia
Hi Amelia,
We must begin with a compliment. Your request is so thorough and has allowed us to positively identify your insect in just a few minutes of web searching. You provided a location, a food plant and a photo. This is not a caterpillar. It is a Striped Alder Sawfly larva, Hemichroa crocea. The larvae are social feeders and BugGuide has an excellent image of a group feeding together.
Letter 4 – Sawfly
Hi there, we live in central/western Canada, and a friend of a friend found this fly on her peonys, I thought it might be a sawfly, but it looks as though it drinks nectar (by its long nose lol!) Any ideas? Thanks alot
Laurie Summers
Saskatchewan,Canada
Hi Laurie,
Definitely a Cimbex Sawfly.
Letter 5 – Probably Sawfly
Can you identify this insect? Does it bite? thanks
This appears to be a Cimbicid Sawfly, but the photo is so blurry we cannot be certain. You did not provide us with a location, but the file is labled “iron mountain fly”. We found an Iron Mountain, Michigan, but we are not certain that is where this photo was taken. Not providing us with helpful information combined with the blurry image makes this identification speculative guesswork. There is a genus of Sawflies, Trichiosoma, that has similar coloration. BugGuide has gotten specimens from Pennsylvania, and that is close to Michigan. Sawflies are nonstinging relatives of wasps. Some have powerful mandibles and can bite, but they are not poisonous.
Thanks much for solving the mystery. Yes, it was seen in Iron Mountain, Michigan. Sorry about the bluriness, it’s menacing appearance must have made my hands shaky.
Letter 6 – Cimbicid Sawfly
This guy was on one of our fenceposts earlier today. It looks like a Scarab Hunter Wasp although it has lobes on the end of it’s antennae which don’t seem to appear in any of the Scarab Hunter photos I’ve seen. If it is a Scarab Hunter I don’t believe it is supposed to be in our area (northwest Washington), is that correct? Do you agree that it is a Scarab Hunter Wasp? At the time of the photograph it was very lethargic and could only fly a few feet and then it would sit still until prodded. Thanks,
Bill Scollard
Granite Falls, Washington
Hi Bill,
This is actually a Cimbicid Sawfly. It is probably in the genus Cimbex. Sawflies are related to wasps, but they do not sting.
Letter 7 – Cimbex Sawfly
I found this little guy on a tree in my yard late August. I’ve never been fond of the creepy crawlies, but I can appreciate a beauty like him. I’ve just found your website, and become rather infatuated with it. It’s quite impressive! He was found in southern West Virginia, about two inches long, completely hairless (I thought this notable, as all other caterpillars I had ever seen had much hair). I took a quick picture and played around with it. I hope it’s not too difficult to identify. I was too bugged out to get much closer. I’ve lived in West Virginia my whole life, but have never seen this species (although I don’t go outside much when the bugs are out). Could you help me out, please? Thanks Much!
Brandi
Hi Brandi,
This isn’t a caterpillar, but a Cimbex Sawfly Larva. The larva of this wasp relative is often mistaken for a caterpillar.
Letter 8 – Sawfly
Hi Daniel,
Glad to hear that you’re up and running. I’ve taken a few shots of some flying insects that I’m unable to identify. You’re help is, as always, greatly appreciated. We found the first fly on the side of our pool. I’ve looked through your fly pages, and haven’t been able to find any matches to the first two fly pictures I’ve sent.
Thanks again!
Yvonne
Barrie, Ontario
Hi Yvonne,
Flies have just two wings. We are requesting Eric Eaton’s assistance with this Hymenopteran. Here is what Eric has to say: “The specimen in question is a sawfly, and it looks to be in the family Argidae, if the last antennal segment is very long, as it appears here. Argids include one recently-introduced species currently found ONLY in Ontario, and this may be it. Would like to have the submitter post it to Bugguide as well, if possible. Thank you. Eric”
Letter 9 – Cimbex Sawfly
Hello.
Hi, we found this in Quebec; it’s a huge and beautiful fly no!
Philippe de France
Hi Philippe,
Your Cimbex Sawfly is beautiful. Thank you for resending it as we were unable to open your first attachment.
Letter 10 – Cimbex Sawfly
Hi, found this huge Wasp/Hornet(We thought at the time) and took some photos of it. Was able to identify it as a Cimbex Sawfly because of your site so I thought I’d send you a few of them. Found Sunday, June 18/2006 at about 8:00pm. Great site,
Thanks.
Andy Kowalski
Hi Andy,
Thanks for sending in your image of a Cimbex Sawfly. The clubbed antennae are a distinguishing feature.
Letter 11 – Italian Sawflies
Hi,
I live in Milan and have a rose creeper on my balcony that has recently become the home for 25+ caterpillars. I have been searching around but I have yet to find out what they are. Your site’s excellent and seems to have everything so I’ve probably just missed it somewhere. Please could you take a look and let me know what you think they might be?
Many thanks!
Lucy
Hi Lucy,
These are not caterpillars which metamorphose into butterflies or moths. These are wasp relatives known as Sawflies. Sorry, can’t tell you the species.
Letter 12 – Tremex columba
Hi WTB…
I found a bug on your site I could not ID. THANK YOU! Interesting enough, you have indicated that it’s found in forests of the Northeast. This guy was photographed on the sidewalk in front of my house in Round Lake, Illinois (far Northeast corner). It’s not the first time I have seen this species but was the first time I had a camera available. Here are two views.
Thanks for the great web site!
Robert Fesus
Buffalo Grove, Illinois
Hi Robert,
We just love it when people look at our site for research and identification. Thanks for the images. When we first posted stories about Pigeon Horntails, we could only locate one image on the web, which we pilfered. Thankfully, we now have several sent to us directly.
Letter 13 – Cimbex Sawfly
WHAT IS THIS???!!!….I heard a buzzing in the trees and found this bug. It was so big and lethargic that it could not fly. I would say it was at least 2 inches long. It moved very slowly and it looked like it was dying. When it was still on the leaf it’s whole body would expand and contract..very yucky..I live in BC Canada..this is the second time I have seen a bug like this in my yard. I did a search on wasps and flys, but I couldn’t find anything that resembled this. Hope you can help!!
Jen
Hi Jen,
We consulted with Eric Eaton to try to get a species name for you, but he arrived at the same generalization we did. This is a Cimbex Sawfly. These are non-stinging relatives of wasps. The larva feed on the leaves of trees, especially willow. Sawflies can be recognized by their club-shaped antennae.
Letter 14 – Sawfly
Can you identify this bug for me, please? Looks like a stonefly, but the head seems to large, the prothorax to small, and no tails. I’m really stumped!
Roger
Hi Roger,
We wanted to be sure, so we contacted Eric Eaton. Here is what he has to say: "The image you sent is actually of a sawfly, but I see the resemblance [to a stonefly]! Without knowing more information, I can’t even tell you which sawfly family this belongs in. However, this is the time of year when sawflies are in greatest abundance here in the U.S. and in Canada.
Eric"
Sawflies are related to ants, bees and wasps, belonging to the order Hymenoptera. Larva of most species feed on foilage. They do not sting.
Letter 15 – Cimbex americana, possibly
We saw this wasp in Vermont on a camping trip in August 2004. It appeared on a large rock. For whatever reason, it did not fly. It was very slow moving, and it stayed in the same spot for a few days. "Cicada Killer" is the first thing that came to mind, but when i got home and looked on the internet I could not find a matching photo. This specimen has white markings, not yellow. It’s thorax and head are black, not brownish. And the legs and antennae are yellow and black. This was the largest wasp/hornet i’ve ever seen. I would say it was close to 2 inches. Can you shed some light as to it’s identity? Thank you for your time.
– Mike V.
Hi Mike,
We wrote to Eric Eaton and he just responded: “My chief suspect is a cimbicid sawfly, Cimbex americana, family Cimbicidae. Behavior fits, as they are slow-moving. They can approach an inch in size, but do not sting. Can bite, though.” Two inches seems rather large and possibly not entirely accurate.
Letter 16 – Elm Sawfly
Seen: Presque Isle River in MI’s U.P. I did not see this on your site.
You couldn’t locate this “caterpillar” because it is not a caterpillar. It is an Elm Sawfly Larva, Cimbex americana, which can be found on Bugguide.
Letter 17 – Club-Horned Sawfly from UK
Found today Doncaster UK. Is this a bee or a mimic ( has mandibles and unusual club ended antennae) ? Many thanks
Gerry Collins
Hi Gerry,
This is a Club-Horned Sawfly in the family Cimbicidae. Cimbicid Sawflies are related to both bees and wasps, and they do not sting. The larvae look like caterpillars and they are frequently mistaken for them.
Letter 18 – Introduced European Saw Flies in Washington???
Letter 19 – European Pine Sawflies
Hi Bugman!
My son found these tiny inchworm-like things on our evergreen shrub today (We live in Michigan). They were in a tight cluster of about 100 worms, each about an inch long. They have tiny, shiny black ball-like heads. In the photo they look hairy, but they aren’t. They are smooth and green all over, with no other markings at all. Upon further inspection, we found several branches of the shrub covered with these things. Several areas of the shrub have been stripped clean of needles, and there are several dying branches as well. At regular intervals (about every 10 seconds) EVERY SINGLE worm on the branch bends straight up, very quickly and in UNISON. It’s quite bizarre to watch. I did check out all of the caterpillar photos on your site, and as a result I ended up looking at Giant Gypsy Moths, Army Worms and Eastern Tent Worms, but none of those look quite like these. I’d say they look most like the Eastern Tent Worm, but there is absolutely no evidence of any tenting or any other type of shelter being formed. Perhaps I just caught them at a very early stage, prior to tent construction? Sorry, these were the best photos I could get. What do I do? They are making short work of my large shrub, and I fear that they will move onto the flowers and vegetables next… Many thanks,
Terri
I think I found it! I believe them to be European Pine Sawflies.
http://woodypestguide.cas.psu.edu/132.htm Now how to get them away from my pine…?
hi Terri,
Once we darkened and sharpened your image, we believe you are correct in your identification of the European Pine Sawfly, Neodiprion sertifer. Your excellent verbal description of their behavior supports the identification. There is an excellent image on BugGuide. There is no danger of them moving to your other plants as most insects are somewhat host specific. You can try hand picking the culprits.
Letter 20 – Elm Sawfly
Hey guys great site!! I’ve got a picture of some sort of bee, or maybe a fly, that landed on me last summer while I was camping in Maine, around the Katahdin area. It was probably about 3/4" long, all black with three white spots on either side and some white between the head and abdomen. I had fun observing him while he crawled around on my hand; he stayed there for quite a while. I looked on every bee and fly page on the site, but didn’t find anything that looked like my little friend. Can you help me? Thanks!
Mischa
Hi Mischa,
What a nice photo of an Elm Sawfly, Cimbex americana. The Elm Sawfly is related to bees and wasps, but does not sting. Its larva looks somewhat like a caterpillar.
Letter 21 – Ichnuemon or Sawfly? Nope: Leucospis species
This little cutie is drilling into my Mason Bee habitats. The block is Douglas-fir, the step shown is about 1/8". She was busy that day, I probably lost many bee larvae but she was delightful to observe. I would be interested in an ID, have not found this particular species in any of my books.
Steve Cameron
Hi Steve,
We would love to know where you are located. How big is the specimen? We are trying to research exactly what she is and the information would be helpful.
Hey, thanks for the rapid reply! These pictures were taken in Portland, OR, USA. My back yard; partially shaded by 2 fruit trees. Many plants native to this area in yard. Small pond within 5 meters of picture location. Subject was about 13 mm to 15 mm, as I recollect. The block that she is working on is a 4×6, or 31
Letter 22 – Army Worms in Ecuador probably Sawflies
Letter 23 – Introduced Pine Sawfly
Letter 24 – Poison Ivy Sawfly
Letter 25 – Skeletonizing Leaf Beetle Larvae, NOT Unknown Sawflies on Coyote Brush
Letter 26 – Sawfly
Letter 27 – Cimbicid Sawfly
Glacier Bee/wasp?
July 13, 2009
Hi there, I’m Shannon from Alaska. I took my friend hiking on Byron Glacier today and found a bee like creature… on the ice! I wasn’t sure at first if he melted out of there or was taking a rest but I’ve never seen anything like him around here. I was hoping you could help?
Shannon from Alaska
Byron Glacier/Portage Alaska
Hi Shannon,
Mistaking this Sawfly for a Bee or Wasp is understandable since Bees, Wasps and Sawflies are all in the same order of insects, Hymenoptera. Sawflies do not sting. We cannot say for sure what species or even what genus your specimen belongs to, but we are confident it is one of the Cimbicid Sawflies in the family Cimbicidae. According to BugGuide: “Adults robust, resemble bumble bees. Base of abdomen broadly joined to thorax (no wasp waist). Antennae have seven or fewer segments, slightly clubbed.” Your specimen is robust and has clubbed antennae. The larvae of Cimbicid Sawflies are often confused with caterpillars because of their appearance and because they feed on foliage. BugGuide lists three genera in the family, and all are represented in the western portion of Canada. At first we thought this might be an Elm Sawfly which is reported from Canada, but now, because all the examples of Elm Sawflies on BugGuide show yellow antennae, we believe this might be a Honeysuckle Sawfly, Trichiosoma triangulum, and BugGuide has an image posted from Montana that looks very similar.
Update from Eric Eaton
Daniel:
The sawfly with the cigarette lighter is, besides causing trouble (ha!), probably Cimbex pacifica.
Eric
Letter 28 – Elm Sawfly
Letter 29 – Elm Sawfly
Letter 30 – Unknown Irish Insect is Transparent Burnet
Letter 31 – Dogwood Sawflies
What’s that caterpillar?
August 14, 2009
Hi —
I love your site and browse it for pleasure when I have time. One damp, overcast morning in August I found an outbreak of these caterpillars on the leaves of my red-bark dogwood shrubs. We live outside of Philadelphia, PA and have had an incredibly wet summer. Any ideas?
Thanks!
Betsy
Merion Station, PA
These are not Caterpillars, but that is a very easy mistake to make. These are the larvae of Dogwood Sawflies in the genus Macremphytus. We are linking to a matching photo on BugGuide. Penn State Woody Ornamental Integrated Pest Management website has a wonderful explanation of the life cycle of the Dogwood Sawfly. It states: “Dogwood Sawfly, Macremphytus tarsatus, is a significant pest to dogwood (Cornus) species. Because the Dogwood Sawfly takes on several forms while in the larval stage, it may not be easy to identify. Even the first instars can devour small portions of leaves, with groups of them producing a skeletonized appearance to the leaves. However, the larger final instar can consume entire leaves, leaving only the tougher leaf midribs.”
Letter 32 – Argid Sawfly, but what species???
Letter 33 – Argid Sawfly
Letter 34 – Leaf Skeletonizer Moth on Euonymus
Letter 35 – Seagrape Sawfly from Honduras
Letter 36 – Elm Sawfly
Letter 37 – False Pine Webworm
Letter 38 – Large Rose Sawflies from UK
Letter 39 – Large Rose Sawfly
Letter 40 – Giant Wood Wasp
I definitely have these in my yard also! They are swarming all over, but they seem to hang out around this one bush I have and my porch, mostly. I’ve never seen them before this year (in Anne Arundel County too). I’m interested in seeing what anyone comes up with for this, because they are everywhere.
Thank you for your comments. With the help of both Eric Eaton and Dave Smith (research entomologist retired from the Smithsonian), I now have the identification for this sawfly. Here is Dave Smith’s comment:
Argidae: A sawfly, Sericoceros mexicanus (Kirby). For a good article on this, see:
Ciesla, W. M. 2002. Observations on the life history and habits of a tropical sawfly, Sericoceros mexicanus (Kirby) (Hymenoptera: Argidae) on Roatan Island, Honduras. The Forestry Chronicle 78(4): 515-521.
The plant must be seagrape, Coccoloba uvifera. Females lay eggs in clusters on the leaf, and stand guard over the eggs until they die. Larvae feed on the leaf edges. Sericoceros mexicanus occurs from southern Mexico to Panama. Other species of the genus are found from Mexico to S. Amer. and in Puerto Rico.
I have these same bugs hanging around the shrub by my front door. I also live in Anne Arundel County. Are they dangerous? I can’t seem to find any information on them online. Above it says it’s a new species. Could we get some more information about them?
Thanks,
kellyjr05
I have these on my roses in Sussex. They lay eggs in the stem of the rose and then all the little larvae eat my rose leaves and buds 🙁
Am currently trying to deter Large Saw Fly larvae from trashing my most treasured rosebush by squirting them and the bush liberally with washing up liquid and water mix – if it doesn’t kill them at least Hopefully it’ll give them a bad stomach ache!! 🙁
How do I get rid of the sawflies the are eating all the new shoots on my penny lane rose?
Hi folks,
Those actually look a bit like sawfly larvae rather than caterpillars. It’s hard to tell with the photo resolution, but there are some social sawflies that move in groups like this…
Cheers,
Bill
Thanks for providing a correction on this nine year old posting. Looking closely, we believe you are correct. We have updated the posting.
Hi folks,
Those actually look a bit like sawfly larvae rather than caterpillars. It’s hard to tell with the photo resolution, but there are some social sawflies that move in groups like this…
Cheers,
Bill
This is first time I’ve spotted this insect on my roses, they sting new , healthy shoots ! are they leaying eggs ? they make lots of damage:( help!!!!!
I live south east of England
Roza
It seems like your observation is correct.
Interestingly I’ve just seen these for the first time on my roses- it looks like it might be a “good” year for them. From other sources it seems they “saw” a track in the young stem and lay eggs in the track, and the larvae when they hatch eat the rose leaves before pupating for next year. Apparently doesn’t usually do huge damage to the plant unless there’s a big infestation but it’s the larvae you need to deal with, not the females laying the eggs. I guess you could cut off the stems affected or deal with the larvae as they emerge.
This is first time I’ve spotted this insect on my roses, they sting new , healthy shoots ! are they leaying eggs ? they make lots of damage:( help!!!!!
I live south east of England
Roza
I’ve just dealt with two of these on my brand new (and very healthy) Pilgrim rose. Never seen them before (I’m in Shropshire, by the way) so I’m very grateful to your website for identifying them.
I found two on my rose bush today. I’ve never seen them before either (I”m in North Hampshire) They took a bit of dislodging, leaving a track behind. I’m also grateful for your identification of them. How long are they usually a problem for? (Weeks/months, in warmer weather?) Does anyone have any recommendations for deterrents or treatment?
I have never seen these fly’s before either i noticed them last week, on my climbing rose bush, i knocked them off with a lolly-pop tick as they seemed to be stuck on the rose bush stem, i wondered what was eating my young shoots in such away, what do you do to get rid of them??? i live in Manchester
I seem to have a swarm of them in my new garden. But there are no damaged roses. Could it be something else?