Caterpillars are an integral part of the Australian ecosystem; gardeners often encounter them in various forms.
From the common green caterpillars munching on your lettuce to the fluffy ones that look almost cuddly, these critters can be both fascinating and frustrating.
How to Identify Caterpillars in Australia
A caterpillar is the immature stage of butterflies and moths (Lepidoptera), and Australia is home to its many species.
The easiest way to identify them is to use your phone camera along with Google Lens or image search. This way, you’ll have access to tons of caterpillar pictures on the web.
But if you’re offline or don’t want to get your phone dirty while you’re gardening, here are a few ways to do it:
- Examine the caterpillar’s colour and pattern. Many caterpillars have distinctive stripes, spots, or unique colourations that can be used to identify them.
- Look at the size and shape of the caterpillar. Some species are long and slender, while others are short and stubby.
- Check for any bristles or spines. These are important features to identify whether the caterpillar is venomous.
- Observe the caterpillar’s behaviour and the type of plant it is feeding on, as some species have specific host plants.
Types of Caterpillars
Australia boasts a wide variety of caterpillars, each with unique characteristics.
Some caterpillars are brightly coloured and easy to spot, while others blend seamlessly into their surroundings.
Common Australian caterpillars
Common caterpillars in Australia are those frequently seen in gardens and natural landscapes.
These caterpillars play a role in the ecosystem but can also pose challenges for gardeners due to their feeding habits.
Armyworm
Armyworms are known for their marching behaviour when they move en masse to new feeding grounds.
They are typically brown or green with distinctive stripes running down their sides.
These caterpillars are highly destructive to crops and lawns, feeding on grasses and grains.
Cabbage White Caterpillar
The cabbage white caterpillar is notorious for its appetite for leafy greens.
It can be found in vegetable gardens across Australia, particularly on cabbage, broccoli, and other cruciferous plants.
This caterpillar is light green with a velvety texture and can quickly defoliate plants if not managed.
Cutworm
Cutworms are named for their habit of cutting down young plants at the base as they feed.
They are usually brown or grey and curl up into a C-shape when disturbed.
Usually found near the soil surface, cutworms can cause significant damage to seedlings and young plants.
Diamondback Caterpillars
These are the larvae or caterpillar form of diamondback or cabbage moths.
Many states across Australia consider them particularly serious and destructive pests. They’re most common in the southern areas and have significant issues with insecticide resistance.
Diamondback caterpillars are a pale greyish-green or yellowish-green with a dark head. More mature caterpillars are a brighter green with a greenish-brown head.
Lily Caterpillars
Lily caterpillars, or spodoptera picta, is a native pest most commonly found in eastern regions of Australia.
Younger caterpillars target and strip leaves, while adults attack leaves and plant crowns.
These caterpillars have very unique markings, with black-and-white bodies and lengthwise yellow or white stripes.
Looper Caterpillars
Looper caterpillars (also called “loopers”) are common across many gardens, but not all of them are pests!
You’ll usually find the harmless native loopers on wattles, eucalypts, and grevilleas. But any looper caterpillar in significant numbers can pose a problem for gardeners.
Loopers range in colour from green to reddish-brown. They’re easily identifiable by their “looping” movement, as they curl into a horseshoe shape then stretch out.
Fluffy Australian caterpillars
Fluffy caterpillars are easily recognisable due to their hair-like bristles, which can vary in colour and length.
While some may seem harmless, others can cause skin irritation upon contact.
Puss Moth Caterpillar
The Puss Moth caterpillar is one of the most distinctive fluffy caterpillars, with dense, silky fur that can range from white to grey.
Despite its cute name and appearance, the Puss Moth caterpillar can deliver a painful sting. So, you’re better off admiring this beauty from a distance.
Southern Old Lady Moth Caterpillar
The Southern Old Lady Moth caterpillar is covered in long, fluffy hairs that can be white or yellowish.
It feeds on a variety of plants, including garden shrubs and trees.
Although striking in appearance, the Southern Old Lady Moth caterpillar’s stinging hairs can cause discomfort when touched.
White-Stemmed Gum Moth Caterpillar
This caterpillar is known for its distinctive white bristles and brown body.
It feeds on eucalyptus leaves and can be found in various parts of Australia.
The White-Stemmed Gum Moth caterpillar’s fluffy appearance makes it easy to spot, but it’s best to handle it with care to avoid skin irritation.
Poisonous Australian caterpillars
Poisonous caterpillars often have bright colours and unusual patterns as warning signs to potential predators.
These caterpillars can cause severe reactions if touched or ingested.
Cup Moth Caterpillar
The Cup Moth caterpillar is another fascinating species found in Australia.
These caterpillars are known for their distinctive and colourful appearance, which often includes bright shades of green, red, and yellow.
Their bodies are adorned with unique cup-shaped spines that can cause irritation if touched.
White Cedar Moth Caterpillar
The White Cedar Moth caterpillar has striking black and white stripes with tufts of poisonous hairs.
It feeds on white cedar trees and can cause allergic reactions in humans and animals.
The distinctive appearance of the White Cedar Moth caterpillar serves as a warning to avoid contact.
Cocky apple stinging caterpillar
This type of caterpillar has stinging hairs that result in a sharp burning sensation on contact. The burn and ache can last up to half an hour.
The larvae are pale yellow and light green, in a flattened oval shape. They’ll have several protrusions (stinging spines) on the sides and along the top.
Both the caterpillars and adult forms are commonly found in the bush, especially during the wet season. Their usual food is the cocky apple or Kakadu plum.
Itchy Australian caterpillars
Several species of Australian Lepidoptera have caterpillars covered in hairs.
These hairy caterpillars can be poisonous, as mentioned above, while others are “non-envenomating.”
This means the hairs don’t contain venom, instead causing irritation or inflammation mechanically.
Processionary Caterpillar
Processionary caterpillars (Ochrogaster lunifer) are named for their habit of moving in long lines, nose to tail. They’re the larvae of bag shelter moths.
They are covered in irritating hairs that can cause rashes and respiratory issues if inhaled.
These hairy caterpillars are typically found in pine trees and other conifers.
Stringybark caterpillar
You’ll commonly find stringybark caterpillars during the wet season, mainly on stringybark trees.
The larva is a chocolate brown colour covered in black tufts of short hairs. There are four larger black tufts beneath the head.
Contact with the larvae, pupae, or even affected tree bark can cause severe itching and potentially swelling.
Grass anthelid
This hairy caterpillar is native to Australia, occurring in many regions. It’s considered a minor and restricted pest.
Also called “woolly bear caterpillars,” the larvae are brown with black or yellow markings, and tufts of dark hairs.
They feed on grass and cereal crops, typically in late winter to early spring.
Types of Caterpillars According to Colour
Caterpillars come in a variety of colours, each often indicating different species and behaviours.
Here are some common types of caterpillars you might encounter in Australia, categorised by their colour:
Black caterpillars in Australia
Black caterpillars are often easy to spot due to their dark colouration.
Here are three common types:
- Black Cutworm: A notorious pest in gardens, capable of destroying entire crops if left unchecked.
- Cherry Dagger Moth Caterpillar: Recognisable by its black body with white and yellow markings.
- Spotted Tiger Moth Caterpillar: Known for its black bristles and distinctive spotted pattern.
Blue caterpillars in Australia
Blue caterpillars, though less common, can be quite striking.
Here are three types you might encounter in Australia:
- Blue Triangle Butterfly Caterpillar: Features a blue body with yellow and white markings.
- Giant Blue Swallowtail Caterpillar: Notable for its large size and blue hue.
- Blue Tiger Caterpillar: Has a vibrant blue and black striped body.
Brown caterpillars in Australia
Brown caterpillars are usually found close to the soil surface.
Here are three common types:
- Cutworms: Known for their ability to cut through the stems of seedlings.
- White-Stemmed Gum Moth Caterpillar: Has a brown body with distinctive white stripes.
- Bogong Moth Caterpillar: Brown and known for their migratory patterns.
Green caterpillars in Australia
Green caterpillars are among the most common and can be quite hard to spot.
Here are three types:
- Cabbage White Caterpillar: Frequently found in vegetable gardens, particularly on leafy greens.
- Emperor Gum Moth Caterpillar: Large, green, and often found on eucalyptus trees.
- Green Looper Caterpillar: Known for its looping movement and green colour that blends with foliage.
Multicoloured caterpillars in Australia
Some caterpillars boast multiple colours, with intricate patterns.
Here are three examples:
- Orchard Swallowtail Caterpillar: Known for its unique, colourful appearance with green, white, and brown patches.
- Spotted Tussock Moth Caterpillar: Features a mix of black, yellow, and white colours.
- Painted Lady Caterpillar: Has a striking combination of black, white, and orange.
Yellow caterpillars in Australia
Yellow caterpillars can be quite striking.
Here are three types you might encounter:
- Spiny Yellow Caterpillar: Not only colourful but also possesses defensive spines.
- Yellow Woolly Bear Caterpillar: Known for its yellow bristles and fuzzy appearance.
- Yellow Admiral Caterpillar: Features bright yellow markings along its body.
Signs of Caterpillar Infestation
Recognising the signs of a caterpillar infestation early can help you take timely action to protect your garden.
Most caterpillars can devour vegetables, fruit trees and other plants, undoing months of care and effort.
So it’s important to be vigilant and look for the following indicators:
Chewed Leaves
One of the most obvious signs of a caterpillar infestation is chewed leaves.
Caterpillars have strong mandibles that allow them to eat through leaves quickly, leaving behind holes or ragged edges.
This damage is usually easy to spot and can affect a wide variety of plants, from vegetables to ornamental shrubs.
Defoliation (losing leaves)
Severe infestations can lead to defoliation, where entire sections of a plant are stripped of their leaves.
This not only weakens the plant but can also hinder its growth and reduce its ability to photosynthesise.
Defoliation is a clear sign that immediate action is needed to control the caterpillar population.
Frass (caterpillar droppings)
Frass, or caterpillar droppings, is another telltale sign of an infestation.
These small, black pellets can often be found on the leaves and around the base of infested plants.
The presence of frass means caterpillars are actively feeding and can help you pinpoint their location.
Silk Webbing
Some caterpillars, like the tent caterpillar, create silk webbing on the branches of trees and shrubs.
This webbing serves as a protective shelter and can contain large numbers of caterpillars.
If you notice silk webs in your garden, inspect them closely for caterpillar activity.
Leaf discolouration and curling
Caterpillar feeding can cause leaves to discolour and curl.
This damage can be mistaken for other plant diseases, but a closer inspection will reveal the caterpillars responsible.
Look under the leaves and along the stems for these pests.
Caterpillar Control is Essential
Caterpillars are an essential part of the ecosystem but can be challenging for expert gardeners and greenhorns.
Understanding the various types of caterpillars in Australia and how to identify them can greatly improve your gardening experience.
Effective caterpillar management involves regular monitoring and prompt action. Recognise the signs of infestation early so you can get rid of caterpillars properly.
