Sawfly Larvae in Australia: How to Identify & Control Them

Found a mob of caterpillar-looking grubs chewing through your bottlebrush, gum tree or paperbark?

Before you declare war on the nearest caterpillar, have another look.

You might be dealing with sawfly larvae.

Sawfly larvae are common in Australian gardens and can look remarkably similar to caterpillars. Some feed quietly on individual leaves. Others gather together in big groups and can strip foliage surprisingly quickly.

And those chunky dark larvae you may have heard called “spitfires”?

They’re sawfly larvae too.

The good news is that finding sawfly larvae does not automatically mean your plant is doomed or that you need to spray the whole garden.

A mature, healthy tree can often handle a bit of chewing. A young bottlebrush being rapidly stripped of its new growth is another story.

This guide will show you:

• how to identify sawfly larvae in Australia
• the difference between sawfly larvae and caterpillars
• which Australian plants they commonly attack
• what sawfly damage looks like
• when you should actually intervene
• how to control sawfly larvae with the least disruption possible
• how to help damaged plants recover

Let’s work out what’s chewing your garden before reaching for a treatment.

Table of Contents:

• What Is a Sawfly?
• What Do Sawfly Larvae Look Like?
• Sawfly Larvae vs Caterpillars: How to Tell the Difference
• What Are Spitfires?
• Common Sawfly Larvae in Australian Gardens
• What Plants Do Sawfly Larvae Attack in Australia?
• What Does Sawfly Damage Look Like?
• Will Sawfly Larvae Kill My Plant?
• Do You Actually Need to Control Sawfly Larvae?
• How to Get Rid of Sawfly Larvae in Australia
• What About Pyrethrum Dust?
• Why Caterpillar Treatments Can Fail on Sawfly Larvae
• How to Help a Plant Recover After Sawfly Damage
• How to Prevent Serious Sawfly Damage
• Sawfly Life Cycle: Why They Can Seem to Appear Suddenly
• Are Sawflies Dangerous to Humans?
• Sawfly Larvae FAQ
• The Bottom Line
• Next Reads for Identifying Chewing Pests Correctly

Not sure whether you’re looking at a sawfly larva or a true caterpillar? Getting a closer look at the legs and body structure can save you from choosing the wrong treatment:

What Is a Sawfly?

Despite the name, a sawfly isn't actually a true fly.

Sawflies belong to the same broad insect order as wasps, bees and ants.

The name comes from the adult female's saw-like egg-laying structure. She uses it to make small cuts in plant tissue before depositing her eggs.

Once those eggs hatch, the larval stage begins.

And this is the stage Australian gardeners are most likely to notice.

Sawfly larvae are soft-bodied, leaf-eating grubs that often look like caterpillars.

Depending on the species, they may feed:

• individually
• in small groups
• packed together along stems and branches
• across the surface of leaves
• from the outer edge of a leaf inward

Young larvae may leave the veins behind and create a skeletonised appearance.

Larger larvae can eat most or all of a leaf.

That can look pretty alarming when dozens decide to have breakfast on the same plant.

What Do Sawfly Larvae Look Like?

There isn't one universal sawfly-larvae colour or shape.

Australian species vary considerably.

Depending on what you've found, sawfly larvae may be:

• dark grey or black
• brown
• greenish
• cream
• patterned or striped
• smooth-bodied
• slightly bristly
• solitary
• tightly clustered together

Many have an obvious rounded head and a long segmented body.

The feature that causes the most confusion is their caterpillar-like appearance.

Fortunately, there's a useful clue.

Sawfly Larvae vs Caterpillars: How to Tell the Difference

Sawfly larvae and caterpillars can look frustratingly similar at first glance.

But they're not the same animal.

The easiest clue: count the prolegs

Look underneath the body.

Along with the three pairs of true legs near the head, you'll see fleshy gripping structures called prolegs running along the abdomen.

Sawfly larvae usually have six or more pairs.

True moth and butterfly caterpillars generally have five pairs or fewer.

No need to wrestle the poor thing into a counting position, either.

A close-up photo from the side is often enough.

Why correct identification matters

This isn't just insect trivia.

If you mistake sawfly larvae for caterpillars, you can end up choosing a treatment specifically designed for true caterpillars and wonder why nothing happens.

Identify first. Treat second.

That's one of the simplest ways to avoid unnecessary spraying in the garden.

If you've confirmed that you're actually dealing with a caterpillar rather than sawfly larvae, jump over to our Caterpillar Pest Control Australia Guide.

What Are Spitfires?

“Spitfire” is a common Australian name given to the larvae of some sawfly species, particularly those associated with eucalypts.

You'll often see them grouped tightly together along a stem or branch.

When disturbed, some sawfly larvae can release an irritating defensive liquid.

Despite the nickname, they aren't breathing fire or launching venom across the backyard.

Still, don't handle unidentified larvae with bare hands.

If you've found a big cluster:

• leave them undisturbed while identifying them
• keep children from poking them
• don't rub your eyes after handling nearby plant material
• wear gloves if removal becomes necessary

The adult sawfly itself does not have the familiar sting people associate with many wasps.

Common Sawfly Larvae in Australian Gardens

Australia has many different sawfly species, but several groups regularly cross paths with gardeners.

Steel-blue sawfly larvae

Steel-blue sawflies are among the better-known Australian sawflies.

Their larvae are often called spitfires and may gather together in noticeable groups.

Eucalypts are important host plants for some species.

A large cluster of dark larvae lined up along a gum-tree branch is a classic sight.

Bottlebrush sawfly

Got larvae munching through a bottlebrush?

Sawfly larvae should be high on your suspect list.

Bottlebrushes can host sawfly species whose larvae consume the foliage.

That can be particularly noticeable on:

• young bottlebrush plants
• fresh new growth
• recently established shrubs
• plants already suffering from drought, transplant shock or another stress

Older, established bottlebrushes are generally in a much stronger position to recover from modest leaf loss.

Long-tailed sawflies

Some sawfly larvae feed on paperbarks and related plants.

Rather than forming the huge, tightly packed groups associated with some spitfires, they may occur individually or in smaller groups.

The basic problem is the same:

Hungry larvae + plenty of leaves = a fairly serious salad bar.

What Plants Do Sawfly Larvae Attack in Australia?

The host plant depends on the sawfly species.

Australian gardeners commonly encounter sawfly larvae on native trees and shrubs including:

• eucalypts and gum trees
• bottlebrush
• paperbarks
• Melaleuca species
• other native trees and shrubs

Seeing chewing damage on one of these plants doesn't automatically prove sawflies are responsible.

Look for the larvae themselves.

Then look at how they're feeding.

That gives you a much better diagnosis than treating the damage alone.

What Does Sawfly Damage Look Like?

Sawfly larvae have chewing mouthparts, so the damage is usually fairly obvious once feeding gets underway.

Early sawfly damage

Small larvae may scrape or eat the softer tissue from a leaf while leaving parts of the vein structure intact.

This produces skeletonised leaves.

You'll see:

• thin or transparent-looking leaf sections
• exposed veins
• patchy surface feeding
• groups of small larvae nearby

More advanced damage

As larvae grow, their appetite grows with them.

You may see:

• large missing sections of leaves
• whole leaves eaten
• bare stems
• rapidly thinning foliage
• upper sections of a plant stripped
• multiple larvae feeding along the same branch

A big infestation can make a tree look absolutely hammered.

But appearance alone doesn't tell you whether control is necessary.

That's the next question.

Will Sawfly Larvae Kill My Plant?

Usually?

Not from one minor attack on an otherwise healthy, mature plant.

Established trees and shrubs carry a significant amount of foliage and are often capable of replacing leaves after a temporary chewing event.

Risk increases when:

• the plant is very young
• most of its foliage is removed
• new growth is repeatedly eaten
• infestations continue for a long period
• the plant is already stressed
• drought or root problems are limiting recovery
• the same plant keeps being defoliated

Think of foliage as the plant's solar panels.

Losing a few panels isn't the end of the world.

Repeatedly stripping almost all of them makes it much harder for the plant to manufacture the energy it needs for recovery and growth.

Do You Actually Need to Control Sawfly Larvae?

This is where a bit of judgement beats spraying first and asking questions later.

You can often monitor rather than treat when:

• the plant is mature and healthy
• only a small amount of foliage is damaged
• there are relatively few larvae
• fresh growth isn't being rapidly stripped
• damage has already stopped
• the plant is recovering normally

Sawflies are part of the garden ecosystem.

Their eggs and larvae can become food for birds, predatory insects and other wildlife.

The goal isn't necessarily to create a completely insect-free backyard.

Consider intervention when:

• a young tree or shrub is being heavily defoliated
• a bottlebrush is losing new growth rapidly
• larvae are present in large numbers
• fresh damage is increasing each day
• most of the plant's remaining foliage is at risk
• the plant has been attacked repeatedly
• the plant is already stressed and struggling

A practical rule:

Protect the plant when the damage threatens its ability to recover.

How to Get Rid of Sawfly Larvae in Australia

Once you've positively identified the pest and decided the level of damage actually warrants action, work from the lowest-impact option upward.

1. Inspect the whole plant

Before doing anything else, work out how large the infestation really is.

Check:

• tops and undersides of leaves
• new growth
• branch junctions
• stems
• nearby plants of the same type

You may find one obvious cluster and assume that's everything.

Sometimes it is.

Sometimes there's another hungry crew three branches over.

2. Remove small infestations manually

If you've only got a manageable number of larvae on a small shrub or young plant, physical removal can be the simplest solution.

Wear gloves and avoid direct contact with unidentified larvae.

Depending on the plant and infestation you may:

• remove accessible larvae carefully
• prune a heavily infested small section
• remove badly affected plant material where appropriate

Don't remove half the plant just to get rid of ten insects.

Healthy green foliage is valuable for recovery.

3. Monitor for fresh feeding

Old leaf damage doesn't heal.

That means yesterday's chewing can make it look like you've still got an active infestation even after the larvae have moved on.

Look for fresh damage.

Check again over the following days and pay attention to:

• newly chewed edges
• new skeletonising
• increasing numbers of larvae
• fresh damage on previously untouched foliage

If the damage isn't progressing, you may not need to do anything else.

4. Give natural predators a chance

Birds and beneficial insects can help keep sawfly populations in check.

This is another reason to avoid reaching immediately for broad-spectrum controls when a mature plant is coping comfortably.

If every insect that lands in the garden is treated as an emergency, you can remove some of the predators that help deal with pest outbreaks naturally.

5. If treatment is necessary, follow the product label

This part matters.

Sawfly larvae may look like caterpillars, but biologically they are different insects.

Do not automatically assume a product labelled for caterpillars is approved or effective for sawfly larvae.

Read the product label and check that:

1. the pest is covered
2. the plant or situation is covered
3. you understand the application directions
4. any withholding period is appropriate for edible plants
5. you can apply it without unnecessarily exposing pollinators or other beneficial insects

If sawfly isn't listed for that use, choose another approach or seek advice rather than guessing.

You can browse our garden pest control range and match your treatment to the pest you've actually identified.

What About Pyrethrum Dust?

Pyrethrum is a broad insect-control ingredient, but the label still matters more than the ingredient name.

Our Pyrethrum Insect Dust Shaker is currently listed for plant pests including aphids, caterpillars and thrips.

Sawfly larvae are not listed there as caterpillars — because they aren't caterpillars.

So don't use the product on sawfly larvae simply because the larvae look similar.

If your closer inspection shows you've actually got a true caterpillar problem, that's different. In that case, the Pyrethrum Insect Dust may be relevant where the crop, pest and application all match the product label.

That's pest control done properly:

right pest, right product, right use.

Why Caterpillar Treatments Can Fail on Sawfly Larvae

Here's one of the easiest mistakes to make.

You see a caterpillar-shaped larva.

You choose a caterpillar-specific biological treatment.

Nothing happens.

The problem might not be the product.

The problem may be that your “caterpillar” was a sawfly larva all along.

Some caterpillar controls work through biological processes that are very specific to moth and butterfly larvae.

Because sawfly larvae belong to a completely different insect group, they may not respond in the same way.

So if a caterpillar treatment seems strangely ineffective, go back to identification before throwing more products at the plant.

Count those prolegs.

How to Help a Plant Recover After Sawfly Damage

Once feeding stops, your priority changes.

Now you're growing leaves, not fighting bugs.

Keep watering sensible

A badly defoliated plant doesn't need to be drowned in sympathy.

Water according to:

• plant size
• soil type
• weather
• drainage
• root condition

Keep the root zone comfortably supplied without turning it into a swamp.

Don't strip off every ugly leaf

Chewed leaves can look terrible.

If part of the leaf is still green, however, that remaining tissue may still be helping the plant photosynthesise.

Remove:

• dead material
• badly damaged sections where necessary
• broken growth
• material that is creating another health problem

But don't turn cosmetic damage into a second defoliation event.

Reduce other stress

A plant recovering from heavy insect feeding has enough on its plate.

Avoid piling additional stress on it through:

• drought
• waterlogging
• unnecessary root disturbance
• aggressive pruning
• excessive fertiliser
• repeated chemical applications

Give it stable growing conditions and watch for fresh growth.

Watch the new leaves

New growth is your best scoreboard.

If the plant begins producing healthy shoots and the feeding has stopped, recovery is underway.

If every new flush gets eaten again, you've got a recurring problem that deserves closer management.

How to Prevent Serious Sawfly Damage

You probably can't prevent every sawfly from ever entering an Australian garden.

Nor do you need to.

Your best defence is early detection.

Check vulnerable plants regularly

Pay extra attention to:

• recently planted bottlebrush
• young gum trees
• paperbarks
• plants that were attacked previously
• fresh new growth

A handful of small larvae is far easier to manage than discovering the plant after most of the canopy has disappeared.

Learn what normal insect activity looks like

Every chewed leaf isn't an emergency.

Every bug isn't a pest.

Regular garden inspection teaches you the difference between:

• minor background feeding
• old damage
• temporary visitors
• a population that's actively increasing

That makes you much faster at recognising a real problem.

Keep plants growing strongly

Healthy plants are generally better equipped to tolerate and recover from moderate leaf loss.

Get the basics right:

• appropriate soil
• sensible watering
• good drainage
• adequate nutrition
• suitable sunlight
• enough room for healthy root growth

Pest management gets much easier when you're starting with a strong plant.

Sawfly Life Cycle: Why They Can Seem to Appear Suddenly

Understanding the life cycle helps explain why yesterday's clean-looking plant can suddenly be covered in hungry larvae.

Sawflies go through four broad stages:

egg → larva → pupa → adult

Eggs

Adult females place eggs into plant tissue using their saw-like egg-laying structure.

Those eggs may be difficult to notice during routine garden checks.

Larvae

The larvae hatch and begin feeding.

This is the stage responsible for most visible leaf damage.

As they grow, they shed their skins and become larger, hungrier and easier to spot.

Pupae

Once mature, sawfly larvae stop feeding and enter a pupal stage.

Depending on the species, this may occur in:

• soil
• leaf litter
• bark
• wood

Adults

The adult sawfly eventually emerges and the cycle begins again.

This is why monitoring matters after an infestation.

Removing the larvae you can see today doesn't necessarily mean another generation can never appear.

Are Sawflies Dangerous to Humans?

Adult sawflies don't sting like many people expect from a wasp relative.

Some sawfly larvae, however, can release an irritating defensive liquid when disturbed.

That's particularly worth remembering around larvae commonly called spitfires.

Avoid deliberately handling them with bare hands.

If you need to work around a cluster:

• wear gloves
• avoid touching your face or eyes
• keep kids from handling them
• wash up after working on the affected plant

Mostly, though, sawflies are a plant-management problem rather than a human threat.

Sawfly Larvae FAQ

Are sawfly larvae caterpillars?

No. They look similar, but sawfly larvae are related to sawflies in the wasp, bee and ant insect group. True caterpillars develop into moths or butterflies. One useful identification clue is the number of abdominal prolegs: sawfly larvae generally have six or more pairs, while true caterpillars normally have five or fewer.

What are spitfire bugs in Australia?

“Spitfire” is a common nickname for the larvae of certain Australian sawflies. They are often seen clustered together on eucalypt branches. Some can release an irritating defensive liquid when disturbed.

Do spitfires actually spit?

Not in the way the nickname suggests. The larvae can produce a defensive liquid, which is why it's best to observe them without poking or handling them.

What do sawfly larvae eat?

Most garden sawfly larvae feed on plant material. In Australian gardens, different species may be found feeding on eucalypts, bottlebrushes, paperbarks and other plants.

Do sawfly larvae kill trees?

A single moderate infestation usually won't kill a healthy mature tree. Repeated or severe defoliation is more concerning, especially on young, establishing or already stressed plants.

Should I remove sawfly larvae from a gum tree?

Not automatically. If you've got a mature, healthy gum and the damage is minor, monitoring may be enough. Intervention makes more sense when a young or stressed tree is being heavily or repeatedly defoliated.

How do I get rid of sawfly larvae naturally?

Start with identification and monitoring. For small infestations you may be able to physically remove larvae or selectively prune heavily infested material. Supporting a diverse garden where birds and beneficial insects are present can also help with natural population control. Escalate only when the level of damage warrants it.

Can I use caterpillar spray on sawfly larvae?

Don't assume so. Sawfly larvae are not true caterpillars. Always check whether the product label covers the actual pest and plant you're treating.

Why didn't my caterpillar treatment kill the sawfly larvae?

Some caterpillar treatments are highly specific to moth and butterfly larvae. If you've actually got sawfly larvae, the treatment may not affect them. Recheck your identification before applying anything else.

What should I do after sawfly larvae have stripped my bottlebrush?

Stop the active feeding first, then support recovery. Keep watering appropriate, avoid unnecessary pruning and allow remaining healthy foliage to keep working. Watch for new shoots. Healthy fresh growth is a good sign the plant is bouncing back.

The Bottom Line

Sawfly larvae can look dramatic.

A big cluster of spitfires or a bottlebrush covered in chewed leaves is enough to make any gardener reach for the pest-control cupboard.

But the smartest first move is simpler:

Work out exactly what you've got.

Sawfly larvae aren't caterpillars.

Not every infestation needs treatment.

And not every pest-control product that works on caterpillars is suitable for sawflies.

For a mature, healthy plant with minor damage, monitoring may be all that's required.

For a young or stressed plant being rapidly stripped, early intervention makes more sense.

The best approach is:

1. Identify the larvae correctly.
2. Check how quickly fresh damage is progressing.
3. Decide whether the plant genuinely needs intervention.
4. Use physical and low-impact controls where practical.
5. Only use a treatment when its label matches the pest and situation.
6. Support the plant while it replaces lost foliage.

That's a much better garden strategy than spraying first and identifying later.

And if your mystery grub turns out to be a genuine caterpillar after all, check out our complete Caterpillar Pest Control Australia Guide for the next step.

Next Reads for Identifying Chewing Pests Correctly

Still finding chewed leaves or mystery grubs? These guides will help you compare similar pests and choose a control method that actually matches what’s feeding on the plant.

• Caterpillar Pest Control Australia Guide
• How to Get Rid of Grasshoppers in Australia
• Garden Weevil Australia: Identification & Control
• Pest Control IPM Stack: Top 10 Organic Solutions

About the Author