Locusts and locust plagues

What are plague locusts

Locusts are large herbivorous insects that can form dense mobile swarms.

There are over 700 species of locusts and grasshoppers in Australia. The 3 main pest locust species in Australia are:

• the Australian plague locust (Chortoicetes terminifera)
• the spur-throated locust (Austracris guttulosa)
• the migratory locust (Locusta migratoria).

The Australian Plague Locust Commission (APLC) has produced a pictorial guide This can assist with the identification of Australian locusts and grasshoppers.

How to identify plague locusts

Of the 3 native species, the Australian plague locust has the most potential to cause damage. This is due to their ability to:

• produce several generations in one year and
• frequently infest large areas, devastating crops and pastures.

Australian plague locusts can be identified from other locust species by:

• the dark spots on the tips of their hind wings
• distinctive red hindleg shanks
• x-shaped marking behind their head which becomes more visible with maturity.

Other important features:

• Their body colour that can vary anywhere from grey to brown and green.
• Adult male locusts measure from 25 to 30 mm long and the tip of their abdomen is smooth and rounded.
• Adult females measure from 30 to 42 mm long and the tip of their abdomen is jagged.
• Young first instar nymphs are usually pale in colour varying to brown and grey and are around 3 mm in size when they hatch. As they develop through the instar stages, it becomes easier to identify them as Australian plague locusts.

A grasshopper and a locust can often be confused as they look similar in appearance. But locusts behave in different ways depending on the density of the population.

In high density populations, locusts undergo behavioural changes. They form gregariously behaving bands of nymphs or swarms.

See our video on what to look for in Australian plague locusts:

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Video transcript

Australian Plague Locusts - What to look for

Hi, I'm Tim Daly, I work for the Local Land Services, Senior Biosecurity Officer.

Australian plague locust is similar to a grasshopper, they're a pest insect species that eats crops and forage on pastures and destroy everything in their path.

So to identify an adult plague locust, they have often got red shanks on their hind legs.

They'll have a dark spot on their wing tips of their hind wings, and they'll often have an 'X' on their thorax which is the top of their shoulders and they can vary in colour from grey to brown to green.

To identify a nymph plague locust, when they hatch they are about 3mm in size, so they are quite small and they are usually a brown/grey colour, and as they develop through their instar stages it becomes easier to identify that they are an Australian plague locust.

Plague locust life cycle - they will hatch from an egg bed into a first instar nymph, and they will go through their development stages.

Each instar generally takes about a week, and they will go through five of those stages until they develop into an adult and fledge and that's when they get on the wing and turn into an adult and get ready to reproduce.

So locusts generally lay their eggs on harder, ridge-type country along roadways and wheel tracks, in paddocks and to identify the egg beds, you like for a series of tiny little holes in the ground and they'll often scratch them over if they have laid the eggs in there.

So a plague locust band will look like millions and millions of small locusts on the ground all together in a band and they will be marching together, going the same direction.

It's really important to know what to look for because they can reproduce at such a rapid rate that it can devastate pastures and crops if they are left untreated.

Problems caused by locust swarms

If left unmanaged, locusts swarms can cause damage to:

• vegetation, crops, pastures
• home gardens, sporting fields and parks.

Locust swarms can migrate over large distances. This can lead to large economic losses for affected landholders, land managers and the community.

Green plants are normally the target feed for locusts . Green pastures (particularly grass species) are at risk of locust attack.

Pressure on individual crops will depend on whether

• there is alternative feed available, or
• whether obstacles such as tree lines affect locusts from moving through the landscape.

Reporting and landholders' obligations

If you become aware of the presence or suspected presence of plague locusts:

You must report it within one business day by contacting your nearest Local Land Services Biosecurity Officer on 1300 795 299.

Locusts in NSW are managed under the Biosecurity Act 2015. This means landholders must:

• report all locust infestations to a Local Land Services authorised officer
• prevent, eliminate or minimise the risk from the locust on their land by treating them with chemical/control agents provided by Local Land Services or with chemical/control agents purchased themselves.

Land managers also have the responsibility to control locusts on public (Crown) lands.

It’s important to remember that landholders and land managers have a general biosecurity duty under the Biosecurity Act 2015.

Landholders’ reports also help build a picture of the statewide situation.

Effective control of plague locusts is most successful when landholders and land managers work together to monitor, report sightings and undertake control programs.

Your reports are used to forecast locust movements, breeding, impacts and required control strategies to help protect farming across the state. 

Local Land Services biosecurity staff are trained in identification of plague locusts. We can help you identify, monitor and control locust populations before they form swarms.

See our video on the importance of reporting plague locusts:

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Video transcript

Australian Plague Locusts - The importance of reporting to Local Land Services

The most important thing is to identify them and tell someone.

Landholders play a critical role in reporting sightings of plague locusts.

We encourage you to monitor your properties and report all activity to the Local Land Services.

I'd never seen plague locust activity before, but it was plain obvious once I saw them, it was like a black lava flowing onto the road here where we are standing.

Look, I did rely on the knowledge of the LLS to tell me when to spray them, and they supplied chemical, free of charge, with advice on how to use it and what rates to use.

Hi I'm Tim Daly, Senior Biosecurity Officer with the Local Land Services.

So it's really important to report sightings of locusts to Local Land Services so we can paint a picture of where these locusts are hatching and we can come out and do an inspection and see what stage they are up to and give you the advice, so we can get the control on them before they start damaging crops and pastures.

The biggest thing is to be vigilant, to be out there looking.

Some people might not have the equipment to be able to handle them themselves, but there is always somebody who will actually come and assist you and get it done.

Current situation and forecast for locusts

The current situation and forecast for locusts is provided by the Australian Plague Locust Commission (APLC). The APLC undertake monitoring and surveillance of locust populations across eastern Australia. The APLC also produces the Locust Bulletin. This provides regional summaries and forecasting of locust activities.

Plague locust control

Controlling plague locusts can be difficult. It's especially difficult during the adult stage when locusts are highly mobile and moving in swarms.

The most effective means of control of this pest is to:

• spray them during the non-flying second to fourth instar stages, when the hoppers start to band together.
• work together with other landholders to monitor, report sightings and undertake control programs concurrently.

In NSW, Local Land Services is responsible for the statewide coordination of locust management.

Our staff work with landholders, the NSW Farmers' Association, and the Australian Plague Locust Commission (APLC) to manage locust populations and reduce the damage they cause.

While Local Land Services takes the lead on plague locust control campaigns in NSW, the APLC can step in to control locust populations in situations where:

• locusts have the potential to inflict significant damage to agricultural industries in more than one state, or
• at the request of the NSW Locust Commissioner.

Support in plague locust control

Local Land Services biosecurity staff:

• are trained to identify locusts and their biology and control options and
• can advise you on the most effective way to monitor and manage them on your land.

Call your nearest Local Land Services Biosecurity Officer on 1300 795 299 or contact us online using the details provided at the end of this page.

Control campaigns

Ideally, ground control is undertaken for locust bands, with aerial control used for swarms.

The most important part of an effective control campaign involves landholders controlling banding nymphs using ground control techniques.

If control becomes beyond the capacity of the landholder, Local Land Services may arrange for ground control contractors to assist. When all ground control options have been exhausted, aerial spraying may be considered.

Aerial control is undertaken for bands and swarms in remote areas. In the semi-arid inland, it is often impracticable for individual landholders to undertake effective control of locusts. Therefore, the APLC and/or LLS may sometimes organise the aerial application of ultra-low volume (ULV) chemicals where the target criteria are met.

Locust control resources

• The Australian Plague Locust Commission is jointly funded by the Australian Government and the member states of New South Wales, Victoria, South Australia and Queensland. It has a series of resources on identifying Australian locusts, the current locust situation, insecticides and the history of locust in Australia.
• Current registered chemicals and locust specific permits can be found using the APVMA’s search function
• Australian Pesticides and Veterinary Medicines Authority
• Safe Meat Australia 
• Plague locusts, wingless grasshoppers and livestock residues factsheet - Safe Meat Australia
• Management of residues following plague locust control FAQ – APVMA
• Wine Industry Locust Control Strategy - The Australian Wine Research Institute.