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.
The sawfly 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 seven 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) also get their names from the plants they feed on. Example: European pine, rose sawfly, elm, birch sawfly, etc.
They go through four stages in life: egg, larva, pupa, and adult. The larvae, otherwise called sawfly caterpillars or rose slugs, are the main culprits behind all the damage.
Below, you’ll learn how to get rid of pine sawfly larvae and others.
Sawfly Larvae Identification
Sawfly larvae resemble small worms, and they are often mistaken for caterpillars by gardeners.
However, 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.
How to Get Rid of Sawflies Naturally
Getting rid of sawflies and their larvae can be simple or complex, depending on how many you have and where you live.
The following are 13 natural sawfly control methods you can try:
1. Crush Larvae
This method is very common, but gross. Simply don a pair of gloves and squish the larvae and/or eggs on the leaves or needles where you find them. Be sure to look under the leaves, as they can attach themselves anywhere to feed.
You can also drop them in insecticidal soapy water to kill them. Additionally, ensure that you get any that fall to the ground.
2. Birds
Once mature, the larvae drop to the ground to pupate in the soil. By tilling the soil, you expose the pupa to birds.
Moreover, placing a feeder by the affected plants will draw the birds initially. The birds will then keep coming back once they have something to feed on. As a result, they will notice any pupae on the ground.
3. Organic Soap Spray
Since the larvae are soft-bodied, a homemade spray made of 4 tablespoons of organic soap and a gallon of water will help get them off plants.
The stickiness will impede their ability to move, and the film left by the soapy water will kill sawflies by means of suffocation.
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.
However, be careful not to use too strong a spray, or you might end up damaging the plant.
5. Diatomaceous Earth
To keep snails off plants like gooseberries and rose bushes, you can spray diatomaceous earth or sprinkle it around the plants being attacked.
This will kill pine sawfly larvae and other species on plants. It will also keep those at ground level from migrating to a new host by cutting up their soft bodies.
Moreover, food-grade DE is non-toxic and works better than Sevin (in my opinion).
6. Kaolin Clay
Applying kaolin clay to plants will keep sawflies and other insect pests away. Just like the diatomaceous earth, the white powdery film will cause irritation.
7. Neem Oil
Neem oil is an all-natural insecticide that comes from the Indian Lilac evergreen’s seeds. It contains azadirachtin, a very potent substance that works against a number of garden pests.
To use, combine 4 teaspoons of neem oil with a gallon of water and a little liquid soap. Spray this homemade sawfly killer on leaves and other affected areas. Reapply after heavy rains.
8. AzaGuard
This is a botanical insecticide that works against a number of insect pests, including sawflies. Its active ingredient is also azadirachtin.
AzaGuard is safe to use in your organic garden.
9. Vacuuming
Use common sense with this option. Placing the nozzle directly on the plant will damage it if you’re not careful.
If the vacuum has strong enough suction and you’re quick enough, you might be able to catch adults before they fly off too.
Once you suck up the larvae, eggs, and any live ones you manage to get, dispose of the critters in soapy water right away.
10. Attract Predators
Sawflies have lots of natural predators. Research will show which species are native to your area and give you tips on how to attract them.
Apart from birds, natural enemies include lizards, parasitic wasps, and frogs. Ladybugs also eat sawfly larvae. Try attracting these natural predators to your garden.
11. Spinosad
This is an organic compound made from fermenting naturally occurring soil bacteria. It works great to control pear slugs, caterpillars, and other garden pests.
Spinosad attacks the pests’ nervous systems, paralyzes them, and then kills them in about two days. You can then wash them off of your plants.
However, the only drawback to using this sawfly treatment is that you cannot use it on eggs. The soft bodies of the pests need to absorb it for it to work, and the eggs have hard shells.
12. Beneficial Nematodes
The nematodes enter the bodies of larvae and pupa and become parasites that eventually kill them.
Place beneficial nematodes in the soil around plants. These creatures will go after the larvae and pupa of bad insects in the soil. However, they will not hurt beneficial organisms such as earthworms.
13. Horticultural Oil
This is also a great natural remedy for rose slugs. When applied, horticultural oil 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 afterward.
This method is one of the best to use for killing the eggs before they hatch and thus saving the plant from further damage.
What Do Sawflies Eat?
Specifically, the larvae and adults eat the leaves and needles of trees and shrubs. However, some feed exclusively on roses, hibiscus, raspberry, and gooseberry.
You may also find sawflies on berberis, plums, bottlebrushes, creeping Jenny, dogwoods, willow trees, mallow, and azaleas. They feed in groups.
Damage to Crops
The damage the larvae can do to the plants they feed on can range from slight to severe. It depends on how many of them there are and the condition of the plants they’re eating.
The pine species is the most common. Sawfly damage to leaves or needles comes in the following forms: holes in leaves, leaves eaten down to the veins, galls on the leaf surface, or rolled-up leaves.
Healthy, mature plants are less susceptible to this kind of damage. However, young or weak plants will show greater damage.
Takeaway
Sawfly worms do not serve any beneficial purpose for plants. While they won’t harm people or animals, they can devastate plant life.
For a healthy garden and/or orchard, getting rid of an infestation is the best course of action.
Using these natural pest control methods will be more beneficial to your plants than any toxic insecticide ever will be.
Thank you so much! This is the most comprehensive article I have seen for dealing with these ornery pests! They devastate my pear tree every year and as an organic gardener I have been struggling to get rid of them. Thanks for the abundance of new “tools”.