How to Get Rid of Cabbage Moths & White Butterflies in Australia

Seen little white butterflies fluttering around the veggie patch, then discovered your broccoli, cabbage, cauliflower or kale full of holes a few days later?

You’ve probably found one of the most common brassica pest problems in Australian gardens.

But there’s an important catch:

What gardeners commonly call a “cabbage moth” is often actually the imported cabbage white butterfly (Pieris rapae).

And it isn’t the only culprit.

Australian brassicas can also be attacked by genuine moth species, particularly diamondback moth (Plutella xylostella) and, in warmer parts of the country, cabbage cluster caterpillar (Crocidolomia pavonana).

All three can leave you staring at chewed leaves and wondering what demolished dinner.

The good news?

Once you know which pest you’re dealing with—and catch the caterpillars while they’re small—they’re much easier to manage.

This guide covers how to identify cabbage moths and cabbage white butterflies, what their eggs and caterpillars look like, how to stop an active infestation, how Bt works, when physical barriers are better than sprays, and how to prevent the next generation from moving in.

If caterpillars are attacking plants other than brassicas too, our broader Caterpillar Pest Control Australia Guide covers the wider range of caterpillar problems found around Aussie gardens.

Table of Contents

• Quick Answer: How Do You Get Rid of Cabbage Moths?
• Cabbage Moth or Cabbage White Butterfly?
• What Is a Cabbage White Butterfly?
• What Does a Cabbage White Caterpillar Look Like?
• What Does a Diamondback “Cabbage Moth” Look Like?
• Don't Forget Cabbage Cluster Caterpillar
• Cabbage Moth Eggs: How to Identify Them
• What Does Cabbage Moth Damage Look Like?
• Can Cabbage and Broccoli Recover After Caterpillar Damage?
• The Cabbage White Butterfly Lifecycle
• When Are Cabbage White Butterflies Active in Australia?
• How to Find Cabbage Moth Caterpillars
• How to Get Rid of Cabbage Moths: The Best Control Strategy
• What About Diatomaceous Earth?
• Do Cabbage Moth Decoys or Eggshells Work?
• Do Companion Plants Repel Cabbage Moths?
• Let the Beneficial Insects Help
• How to Prevent Cabbage Moths Coming Back
• Common Cabbage Moth Control Mistakes
• Cabbage Moth Control: A Simple 7-Day Plan
• Frequently Asked Questions
• The Bottom Line
• Next Reads for Keeping Caterpillars Off your Veggie Patch

Want the quickest control setup? These are the tools that make the two key jobs—excluding adults and controlling young caterpillars—easier:

Quick Answer: How Do You Get Rid of Cabbage Moths?

The most reliable cabbage moth control combines early inspection, hand removal, fine insect netting and targeted control of small caterpillars.

1. Check brassicas for eggs and young caterpillars.
2. Remove any eggs and caterpillars you can see.
3. Cover clean plants with properly sealed insect netting.
4. If treatment is needed, use an appropriately registered product such as Bt according to its label while caterpillars are small and feeding.
5. Recheck the crop every few days until fresh chewing and frass stop appearing.

Acting early is much easier than controlling large caterpillars after they have moved into cabbage hearts, broccoli florets or cauliflower curds.

Cabbage Moth or Cabbage White Butterfly?

This is where a lot of online gardening advice gets muddled.

If you're seeing a white butterfly flying around during the day, you're most likely looking at the cabbage white butterfly (Pieris rapae), rather than a moth.

If you're seeing a tiny grey-brown moth, particularly when the plants are disturbed or around dusk, diamondback moth becomes a stronger possibility.

And if you're in a warmer northern area and find groups of caterpillars feeding together under webbing, cabbage cluster caterpillar should be on your suspect list.

Here's the quick comparison.

Identifying the pest matters because its behaviour tells you where to look and when to treat.

What Is a Cabbage White Butterfly?

The cabbage white butterfly (Pieris rapae) is an introduced species now common in Australian gardens. Adults are around 4–5 cm across, with creamy-white wings, darker tips and black forewing spots. Males generally have one spot on each forewing, while females have two.

You will often notice the adults before you find any damage. They have a wandering, fluttery flight over broccoli, cabbage, cauliflower and other brassicas while females search for suitable leaves on which to lay eggs.

Adult butterflies do not chew the crop; their caterpillars do. A white butterfly repeatedly visiting the brassica patch is therefore an early warning to start checking leaves for newly laid eggs.

What Does a Cabbage White Caterpillar Look Like?

The cabbage white caterpillar—sometimes called a cabbage worm—is green and beautifully camouflaged against brassica leaves.

Look for:

• a soft or velvety green appearance
• fine hairs
• faint yellowish lines
• caterpillars reaching roughly 30 mm when mature
• greenish droppings around feeding areas

Their camouflage is surprisingly good.

Sometimes you'll notice the droppings or leaf damage before you see the caterpillar itself.

When searching, look along:

• leaf veins
• the undersides of leaves
• folded leaves
• the central growing point
• broccoli florets
• cauliflower curds
• the developing cabbage heart

Young larvae are much easier to control than mature ones, so don't wait until you've got chunky green caterpillars staring back at you.

What Does a Diamondback “Cabbage Moth” Look Like?

The diamondback moth is a genuine moth and a serious brassica pest.

The adults are tiny—only around 10–12 mm long—and usually greyish or brown.

When the wings are folded, males can show the pale diamond-like markings responsible for the name “diamondback moth”.

Its caterpillars look quite different from a mature cabbage white caterpillar.

Diamondback moth larvae are generally:

• small
• pale yellow-green
• tapered at both ends
• around 12 mm when mature
• very wriggly when disturbed

Here's a handy identification trick:

Touch or disturb one gently.

A diamondback moth caterpillar may wriggle backwards quickly and can drop from the leaf on a fine silk thread.

Young larvae can initially feed within leaf tissue. As they grow, the classic symptom is often windowing—thin, translucent patches where much of the leaf tissue has been eaten but part of the surface remains.

Those windows eventually tear and become holes.

Diamondback caterpillars can also work their way into broccoli florets, cauliflower curds and cabbage heads, where they become much harder to reach.

That's another reason early control matters.

Don't Forget Cabbage Cluster Caterpillar

Gardeners in Queensland and northern New South Wales should also know the cabbage cluster caterpillar.

This pest tends to be more important in warm weather, particularly through summer and early autumn in northern growing areas.

Rather than finding one beautifully camouflaged caterpillar here and there, you may discover groups feeding together.

Watch for:

• egg masses underneath leaves
• groups of young caterpillars
• heavy feeding in the centre of plants
• webbing
• lots of frass or droppings
• badly skeletonised leaves

Young caterpillars start pale or semi-translucent with dark heads and become greener with cream or yellowish striping as they develop.

A colony can cause serious damage surprisingly quickly.

Cabbage Moth Eggs: How to Identify Them

The phrase “cabbage moth eggs” can refer to several brassica pests. Their colour, shape and laying pattern can help you identify the culprit before new leaf damage appears.

Cabbage White Butterfly Eggs

Cabbage white butterfly eggs are small, pale cream to yellow, elongated or bullet-shaped and vertically ridged. They are normally laid singly on brassica leaves, including the undersides.

They are easy to miss if you only search for caterpillars. Turn the leaves over and inspect them every few days, particularly after adult white butterflies have been visiting the patch. Squash or lift off individual eggs before they hatch.

Diamondback Moth Eggs

Diamondback moth eggs are much smaller—around half a millimetre—and pale yellow. They may occur singly or in small groups on stems or leaves.

Cabbage Cluster Caterpillar Eggs

Cabbage cluster caterpillar eggs are laid in larger, more obvious masses, normally underneath the leaf.

The laying pattern matters: a single upright egg points more strongly towards cabbage white butterfly, while a larger egg mass in a warm northern growing area should put cabbage cluster caterpillar on your suspect list.

What Does Cabbage Moth Damage Look Like?

Different species create slightly different damage, but there are several classic signs.

Irregular Holes in Leaves

This is typical caterpillar feeding.

Cabbage white caterpillars can chew substantial sections from the leaf as they grow.

Window-Pane Damage

Small diamondback moth larvae often create translucent “windows” in the leaf.

If you see lots of small thin patches before obvious holes develop, get your glasses on and look closely.

Damaged Growing Points

This matters most on young brassicas.

A plant can tolerate some damage to older outer leaves. Destruction of the central growing point is a much bigger problem.

Caterpillars Inside Heads and Florets

Broccoli and cauliflower offer plenty of hiding spots.

Once caterpillars work deep into compact growth, spray coverage becomes difficult and finding every larva turns into a treasure hunt nobody asked for.

Frass

That's the polite gardening word for caterpillar poo.

Fresh green or dark droppings sitting on leaves, in broccoli heads or around the heart of the plant are a strong sign something is actively feeding above them.

Webbing

Heavy webbing combined with groups of caterpillars points more strongly toward cabbage cluster caterpillar than cabbage white butterfly.

Can Cabbage and Broccoli Recover After Caterpillar Damage?

Often, yes.

A few ugly leaves don't necessarily mean the plant is finished.

An established brassica with a healthy central growing point can tolerate surprisingly rough treatment.

What matters is:

• how much foliage remains
• whether the growing point has been destroyed
• how young the plant is
• whether caterpillars are still actively feeding
• how much time remains in the growing season

First, stop the active damage.

Then give the plant good growing conditions and let it rebuild.

Don't remove every damaged leaf just because it looks ugly. If a leaf still contains plenty of healthy green tissue, it's still photosynthesising and helping the plant recover.

Which Plants Do Cabbage Moths and White Butterflies Attack?

Brassicas are the main buffet.

Common targets include:

• cabbage
• broccoli
• cauliflower
• kale
• Brussels sprouts
• bok choy
• pak choi
• turnips
• radishes
• mustard greens
• rocket
• kohlrabi

Cabbage white caterpillars can also turn up on other related or suitable host plants around the garden, including nasturtiums.

If one brassica is being hammered, check its neighbours as well.

The Cabbage White Butterfly Lifecycle

Understanding the lifecycle makes control much easier.

It follows four stages:

Egg → Caterpillar → Pupa → Adult Butterfly

The female lays an egg on a suitable host plant.

The egg hatches and the caterpillar begins feeding.

The caterpillar grows through several stages, eating progressively more as it gets bigger.

Once mature, it forms a pupa or chrysalis attached to a plant or nearby surface.

The adult butterfly eventually emerges and the cycle begins again.

In warm conditions, generations can turn over quickly.

Which means killing the caterpillars you happen to see today doesn't necessarily finish the infestation.

There may still be:

• unhatched eggs
• tiny larvae you missed
• pupae nearby
• new adult butterflies arriving

Think lifecycle, not one-off spray.

That's the difference between pest management and playing whack-a-mole with caterpillars.

When Are Cabbage White Butterflies Active in Australia?

There's no single Australia-wide cabbage butterfly season because Cairns, Sydney, Melbourne and Hobart don't share the same climate.

Generally, warmer conditions and actively growing brassicas favour pest activity.

Cabbage white butterfly activity is often obvious through the milder and warmer parts of the growing season, while warm regions can experience pressure for much longer.

Diamondback moth populations can also build quickly during favourable warm conditions.

Cabbage cluster caterpillar is especially worth watching through summer and early autumn in northern NSW and Queensland.

Rather than relying purely on the calendar, watch the garden.

Increase your inspections when:

• daytime temperatures warm up
• brassicas are producing soft new growth
• white butterflies start visiting
• tiny moths lift from plants when disturbed
• fresh holes appear
• frass suddenly appears
• nearby brassica weeds are carrying caterpillars

For vulnerable crops, checking leaves two or three times a week during active periods is much easier than rescuing a plant that's already been stripped.

How to Find Cabbage Moth Caterpillars

Do not stand over the garden waiting for one to wave at you. Use the same inspection order on every plant.

1. Start With the Newest Damage

Old holes do not heal, so find leaves with fresh-looking chewing before deciding the pest is still active.

2. Look Underneath the Leaves

Eggs and young caterpillars often avoid the obvious upper surface. Turn leaves over and inspect along the veins.

3. Follow the Frass

Fresh caterpillar droppings usually mean an active larva is nearby. Look directly above and around the frass.

4. Check the Centre and Compact Growth

Inspect inner leaves, growing points, cabbage hearts, broccoli florets and cauliflower curds. Small caterpillars become much harder to find once they move into tight growth.

5. Gently Disturb the Plant

Tiny diamondback moth larvae may wriggle violently or drop from the leaf on silk when disturbed.

6. Search in Good Light

Early morning or late afternoon inspections are easier than trying to identify a 5 mm green caterpillar in harsh midday sun.

Where to Check on Each Brassica Crop

How to Get Rid of Cabbage Moths: The Best Control Strategy

There's no need to reach immediately for the strongest insecticide on the shelf.

The smartest strategy is an integrated pest management approach, or IPM.

Use the least disruptive method that will solve the problem, then escalate only if you need to.

1. Remove Eggs by Hand

If you find the infestation early, egg removal can be ridiculously effective.

Squash or lift off individual eggs. Only remove a small piece of leaf when that is the practical way to dispose of an egg mass and the plant will not lose a meaningful amount of healthy foliage.

It is much easier to deal with an egg today than the hungry caterpillar that comes out of it later.

For a small backyard brassica patch, this should be one of your first moves.

2. Pick Caterpillars Off by Hand

Not glamorous.

Very effective.

If you've got six cabbages and five caterpillars, don't overcomplicate it.

Pick them off.

Check:

• leaf undersides
• stems
• central shoots
• folds
• broccoli heads
• cauliflower curds

Hand removal works especially well alongside netting because you're physically cleaning up the current generation before blocking the next.

For larger or mixed infestations, see our complete guide to caterpillar control in Australian gardens.

3. Use Fine Insect Netting Before They Lay Eggs

For cabbage white butterflies, physical exclusion is one of the smartest preventative strategies available.

No adult access means dramatically fewer opportunities for egg laying.

Cover brassicas with fine insect mesh and make sure the edges are properly sealed.

That's important.

A loose net floating above the crop with a 10 cm invitation underneath isn't pest exclusion. It's shade cloth with a front door.

Make sure:

• there are no major holes
• the mesh isn't trapping butterflies inside
• edges are secured
• leaves aren't pushing awkwardly through gaps
• plants are inspected before being covered

That last point is critical.

Never assume netting cures an infestation already underneath it.

If eggs or caterpillars are on the plants when you cover them, you've just created a lovely protected dining room.

Inspect first. Net second.

The same physical-exclusion principle is why products such as our Reusable Fruit Protection Bags work well for individual fruit clusters. For cabbage, broccoli and cauliflower, however, covering the whole brassica bed with suitable insect netting is generally far more practical than bagging individual leaves.

4. Use Bacillus thuringiensis (Bt) While Caterpillars Are Small

For active caterpillar infestations on edible crops, Bacillus thuringiensis, usually shortened to Bt, is one of the most useful targeted tools.

But you've got to understand how it works.

Bt isn't primarily about coating the caterpillar in something nasty.

The caterpillar needs to eat treated plant material.

After ingesting an appropriate Bt formulation, susceptible caterpillars stop feeding and later die.

That tells you exactly how to get better results:

• treat while caterpillars are small
• achieve good leaf coverage
• pay attention to the undersides of leaves
• target areas where larvae are actively feeding
• follow the label
• recheck the crop afterwards

Bt becomes less reliable if you wait until caterpillars are large.

It can also degrade in sunlight and may be washed from foliage by rain or overhead watering, so application timing matters.

Don't spray immediately before irrigation or a downpour and then wonder why nothing happened.

Always use a Bt product registered for your intended pest/crop situation and follow its current Australian label directions, including rates, reapplication and withholding instructions.

5. Where Does Pyrethrum Fit?

Pyrethrum is a contact insecticide, which makes it quite different from an ingested caterpillar treatment such as Bt.

That means it can be useful when the target pest is exposed and the product label confirms the intended use.

Our Pyrethrum Concentrate is designed to be diluted and applied as a targeted contact spray where its label permits.

We also stock Pyrethrum Insect Dust, which lists caterpillars among its target pests.

But there's an important gardening point here:

Pyrethrum is broad-spectrum.

It may also affect beneficial insects that contact it.

So don't treat it like holy water and spray the whole garden because you saw one white butterfly.

Use it selectively, avoid unnecessary application to flowers and beneficial-insect activity, and always follow the label for approved plants, pests, withholding periods and safety directions.

For cabbage caterpillars specifically, early identification, hand removal, exclusion and targeted caterpillar controls should usually form the backbone of the strategy.

What About Diatomaceous Earth?

Diatomaceous Earth can be useful for targeted management of certain crawling pests around plants, pots, growing media and garden areas. It is not the primary control recommended here for an established cabbage white or diamondback moth caterpillar outbreak.

Do not let a general garden treatment replace the actions that match this pest problem: inspect the brassicas, remove eggs and caterpillars, exclude adult butterflies and moths, and use an appropriately registered caterpillar treatment when required.

Treat diatomaceous earth as one possible tool in a broader IPM kit, not as a substitute for controlling larvae that are actively feeding on the crop.

Do Cabbage Moth Decoys or Eggshells Work?

Fake white butterflies and scattered eggshells rely on the same idea: a cabbage white butterfly will supposedly see another white object, assume the territory is occupied and lay somewhere else.

There are anecdotal reports from gardeners who believe these tricks reduce visits, but neither should be treated as dependable cabbage moth control. They are not substitutes for properly fitted insect netting, regular inspection and early control of caterpillars.

If you enjoy garden experiments, there is no harm in testing decoys or eggshells as an extra deterrent. Just do not leave a valuable broccoli or cabbage crop unprotected because a few white objects are standing guard.

Do Companion Plants Repel Cabbage Moths?

Do not treat companion plants as a dependable repellent. Growing herbs or flowers beside cabbage does not create an invisible barrier, and adult butterflies and moths can still find brassicas.

Companion planting can still add diversity to the patch, but use direct monitoring and physical exclusion when the crop needs reliable protection. Its most defensible pest-management value is supporting a broader garden ecosystem, covered in the next section.

Let the Beneficial Insects Help

Not every insect in the veggie patch is your enemy.

Cabbage caterpillars have natural enemies, including parasitic wasps and a range of predators.

Some tiny parasitoid wasps lay their eggs in or around caterpillar hosts. Their developing offspring eventually kill the caterpillar.

You may occasionally find a cabbage caterpillar surrounded by tiny white or pale cocoons.

If so, don't assume you've discovered a bizarre new pest and squash the whole lot.

You may be looking at evidence that natural biological control is already happening.

Supporting beneficial insects means:

• avoiding unnecessary broad-spectrum spraying
• growing a variety of flowering plants
• providing habitat
• tolerating a small amount of pest activity where practical
• treating only when damage justifies it

You don't need a totally insect-free garden.

You need a garden where pests don't reach damaging numbers.

That's a very different goal.

How to Prevent Cabbage Moths Coming Back

Once the active infestation has been cleaned up, focus on stopping eggs and unnoticed larvae from starting the cycle again.

Inspect Seedlings Before Planting

Check both sides of every leaf so eggs or tiny caterpillars are not introduced with new seedlings.

Net Young Brassicas Early

Cover clean plants before white butterflies begin visiting heavily. Continue checking beneath the net for gaps, trapped adults or pests that were present before installation.

Remove Infested Brassica Debris

After harvest, remove heavily infested crop debris rather than leaving it beside the next planting.

Check Brassica-Family Weeds and Volunteers

Related weeds and volunteer brassicas can maintain pest populations close to the vegetable patch.

Protect Seedlings and Growing Points Closely

Established kale may tolerate limited chewing, but a young seedling can be set back badly if its central growing point is destroyed.

Use a Layered IPM Program

Do not depend on repeated use of one insecticide. Diamondback moth is well known for insecticide resistance, making monitoring, exclusion, hand removal and selective treatment more dependable as a combined strategy.

Common Cabbage Moth Control Mistakes

Waiting Until Caterpillars Are Large

Small larvae are easier to find and control and have caused less damage.

Inspecting Only the Tops of Leaves

Always check undersides, veins, folds and central growth.

Treating Old Holes Instead of Active Feeding

Old holes remain after the pest has gone. Confirm fresh chewing, frass, eggs or larvae before treating.

Netting an Infested Crop

Inspect and clean the plants before sealing the net so existing eggs and caterpillars are not trapped inside.

Reaching for Broad-Spectrum Spray First

Use the least disruptive effective option and reserve broader contact insecticides for situations where they are justified and permitted by the label.

Treating Once and Ignoring the Lifecycle

Eggs may hatch after the first inspection, so recheck the crop rather than assuming one treatment ended the infestation.

Assuming “Organic” Means Harmless to Beneficial Insects

Natural origin does not automatically mean selective. Pyrethrum can affect non-target insects, so use it carefully and according to the label.

Cabbage Moth Control: A Simple 7-Day Plan

If your brassicas are being eaten now, use this schedule after reading the detailed control methods above.

Day 1: Inspect and Remove

Inspect every plant and remove visible eggs and caterpillars, paying particular attention to leaf undersides and compact growth.

Day 1–2: Treat if Required

If numerous small caterpillars remain, apply an appropriately registered Bt product according to its label.

Day 3: Check for Fresh Activity

Look for new chewing or fresh frass rather than judging the result by old holes.

Day 4–5: Catch Newly Hatched Larvae

Inspect again for caterpillars that may have hatched after the first check.

Day 7: Exclude the Next Adults

Once the crop is clean, install or repair insect netting and continue weekly checks.

Frequently Asked Questions

Is a Cabbage Moth the Same as a Cabbage White Butterfly?

Not technically. Australian gardeners often call the cabbage white butterfly (Pieris rapae) a “cabbage moth”, but genuine brassica moth pests include diamondback moth and cabbage cluster caterpillar.

What Is a White Cabbage Moth?

If the insect is clearly white and flies around cabbage or broccoli during the day, it is most likely a cabbage white butterfly rather than a moth.

Is a Cabbage Worm the Same as a Cabbage White Caterpillar?

“Cabbage worm” is a common overseas name for cabbage-feeding caterpillars, particularly Pieris rapae larvae. Australian gardeners are more likely to call them cabbage white caterpillars.

What Kills Cabbage White Caterpillars?

Hand removal works for small numbers. Where larvae are numerous, an appropriately registered Bt product can provide targeted control while they are small and feeding. Netting helps prevent adults from laying the next generation.

When Should I Spray Bt?

Use Bt while caterpillars are small and actively feeding. Follow the current product label and avoid timing that allows immediate rain or overhead watering to wash it from the foliage.

Does Bt Kill Butterfly Caterpillars Too?

Bt products targeting Lepidoptera can affect susceptible moth and butterfly larvae that eat treated foliage. Apply them only to the crop being protected and avoid treating host plants deliberately grown for desirable butterfly species.

Should I Kill Cabbage White Butterflies?

Concentrate on protecting the crop rather than chasing individual adults. Properly fitted netting prevents egg laying, while inspection catches eggs and young caterpillars.

Why Do I Still Have Caterpillars Under My Insect Netting?

Usually, eggs or caterpillars were already present, an adult entered through a gap, or the net was not sealed. Remove the cover, inspect and clean the plants, then repair and reinstall the net securely.

The Bottom Line

When white butterflies or small moths begin visiting brassicas, inspect the crop before serious damage develops. Correct identification, early removal and properly fitted netting will prevent many outbreaks; targeted treatment is most effective while caterpillars are still small.

If caterpillars are attacking more than the brassica patch, use our full Caterpillar Pest Control Australia Guide for the broader approach.

Your cabbages do not need to look perfect. They just need to reach your plate before the caterpillars do.

Next Reads for Keeping Caterpillars Off your Veggie Patch

Still seeing chewed leaves or new caterpillars appearing? These guides will help you identify other likely pests, time your controls better and build a broader IPM strategy.

• Caterpillar Pest Control Australia Guide
• Pest Control IPM Stack: Top 10 Organic Solutions
• Which Pest When? Australia
• Companion Planting for Organic Pest Control

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