So named because of the shape of the tube-like organ the female uses to pierce open plants to lay its eggs in, sawflies are in the same group as bees, ants, and wasps.
It resembles a fly but is more like a wasp, only it doesn’t sting. They’re dated as far back as the Triassic period and have over 8,000 species split into 7 superfamilies.
All but one of these families feed exclusively on plants. This last of these harmful garden insects feeds on wood-boring beetles.
Sawflies (Symphyta) are labeled as a result of the plants they feed on, not eating anything else. Example: European pine, rose sawfly, elm sawfly, birch sawfly, etc.
They go through four stages in life — egg, larvae, pupa, and adult. The larvae, otherwise called sawfly caterpillars, are the main culprit behind all the damages.
Below you’ll learn how to get rid of pine sawfly larvae and others.
Sawfly Larvae Identification
Sawfly larvae resemble pesky caterpillars, and they are often mistaken for them by gardeners.
They must be properly identified because most of the methods used to get rid of caterpillars don’t work on them.
Help with identification can be found at Wildlife Insight. Some families have larvae that are identical to slugs; hence, the name rose slugs. All range in size and colors depending upon the plants they eat.
How to Get Rid of Sawflies Naturally
Getting rid of them can be simple or complex depending upon how many you have and where you live.
The following are 13 natural sawfly control methods or getting rid of sawflies and their larvae.
1. Crush Larvae
This method is one of the two most often used, and it’s the grossest. Simply don a pair of gloves and squish the larvae on the leaves/needles where you find them.
The pupa of sawflies drop to the ground most times and grow in soil. By cultivating the soil, you expose the pupa to birds that make them a feast during cold months.
Placing a feeder by the plants being eaten will draw the birds initially, and they will keep coming back once they notice the pupa on the ground.
During warm months, this will also attract them to where the larvae are feeding and where they fall onto the ground once they’re done with the leaf they were eating.
3. Organic Soap Spray
Since the larvae are soft-bodied, using a spray made of 4 tablespoons of organic soap in a gallon of water will help get them off plants and kill them.
The stickiness will impede their ability to move and the film left by the soapy water will eventually suffocate and kill them.
4. Use the Water Hose
Showering the plants with water will not only give the plants a drink, but it can also knock the worms off the plants killing them.
Be careful not to use too hard of a spray, or you’ll end up tearing up the plant, possibly even killing it by damaging it too much.
5. Diatomaceous Earth
DE is a powder made from fossils left in mineral deposits with tiny shards of shell and bone.
Used to keep snails off plants like gooseberries and rose bush, diatomaceous earth can also be sprayed on or sprinkled around the plants being attacked.
This will kill the larvae on the plant and keep those at ground level from migrating to a new host by cutting up their soft bodies. The product works better than Sevin and it’s non-toxic.
6. Kaolin Clay
This is a clay mineral containing mostly silica. Placing kaolin clay around the base of your plants will keep the larvae from traveling from one plant to another — they can’t fly in this stage.
Because they are soft-bodied, the silica will cut them up, just like the diatomaceous earth does, and this will kill them.
7. Neem Oil
Neem oil is an all-natural insecticide made from the Indian Lilac evergreen’s seeds. It contains Azadirachtin, a very potent substance that works against a number of insect pests.
By combining 4 teaspoons in a gal. of water and a little liquid soap, this homemade sawfly killer is sprayed on leaves and other affected areas to keep them from eating. Reapply after heavy rains.
8. Manually Remove
Removal by hand is the other most commonly used method, and it’s a lot less hectic than the other ones already mentioned.
Donning a pair of gloves, you simply pluck the larva and/or eggs from the areas where you find them. Be sure to look under the leaves as they can attach themselves anywhere to feed.
You can then either smash them or put them into insecticidal soapy water — both will kill. Be sure you get any that fall onto the ground, or it will just move to another plant.
Use common sense with this option. Placing the nozzle directly on the plant will damage it, even kill it if you’re not careful.
If the vacuum has strong enough suction, and you’re quick enough, you might be able to get adults before they fly off too.
Once you’ve sucked up the larvae, eggs, and any live ones you manage to get, disposal into soapy water right away is highly recommended.
10. Attract Predators
Sawflies have lots of natural predators in the insect world. Research will show which are native to your area and give you tips on how to attract them.
Predators will include predatory beetles such as lady beetles (who knew!) and parasitic wasps. Only methods attracting predatory insects who are native to your area will work, of course.
This is an organic compound made from fermenting naturally occurring soil bacteria.
Spinosad attacks the insect’s nervous system, paralyzes them, and then kills them in about two days. The insect can then be easily washed off the plants.
The only drawback to using this method is it can’t be used on eggs; it needs to be absorbed directly into the soft body of the pest to work, and the eggs have hard shells.
12. Beneficial Nematodes
Microscopic roundworms, nematodes enter the bodies of larvae and pupa and become parasites that eventually kill them.
Placed in the soil around plants, these creatures will go after pests with larvae or pupa in the soil, and they will move from dead pest to dead pest until none are left.
They don’t hurt anything but insect pests making them one of the best insect predators to use.
13. Horticultural Oil
Horticultural oil contains mineral oil and when applied, it covers the sawfly eggs and larvae in a thick film which eventually suffocates them.
The oil itself won’t harm the plant and will wash off once its job is done.
This method is one of the best to use for killing the eggs before they hatch and thus, saving the plant from further damage, or even death.
What Do Sawflies Eat?
Specifically, the larvae and adults eat the leaves and needles of trees and shrubs, including several which feed exclusively on roses, hibiscus, raspberry, and gooseberry.
You may also find sawflies on berberis, plum, bottlebrush, creeping Jenny, dogwood, willow, mallow, and azalea.
They feed in groups of 30-90, sometimes more, and when they’re done on one leaf, they move to another.
Damage to Crops
The damage the larvae can do to the plants they eat can range from a few leaves to an entire orchard being completely denuded.
It depends on how many there are and on the condition of the plants they’re eating.
The pine species is the most common. Damage to leaves/needles comes in the following forms: holes, notches, eaten down to the veins, galls on the leaf surface, leaves rolled up, and webs.
Healthy, mature plants are less susceptible to this kind of damage, but young/weak plants can be injured or killed. Injuries come in the form of stunted or stopped growth.
Sawflies, especially their larvae do not serve any beneficial purpose to plants. While they won’t harm people or animals, they can, and do, devastate plant life.
For a healthy garden and/or orchard, getting rid of an infestation is the best course of action.
Doing it naturally is the most ecologically sound method as it prevents you from harming your plants as well as the beneficial insect life.
Using these natural methods, and others like them will be more beneficial to your plants than any toxic insecticide ever will be.