Locusts

Australian plague locust swarms can devastate crops and cause major agricultural damage. As a landholder it is vital that you know what to do if you suspect plague locusts in NSW. Local Land Services staff can help you identify and control plague locusts on your property.

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 Commission (APLC) has produced a pictorial guide to 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 and distinctive red hindleg shanks. Another distinctive feature is the x-shaped marking behind their head which becomes more visible with maturity. Their body colour 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, however locusts behave in different ways depending on the density of the population. In high density populations, locusts undergo behavioural changes and form gregariously behaving bands of nymphs or swarms.

What problems are 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, leading to large economic losses for affected landholders, land managers and the community.

Green plants are normally the target feed for locusts with green pastures (particularly grass species) 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 which means:

landholders must report all locust infestations to a Local Land Services authorised officer
landholders must 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 and can help you identify, monitor and control locust populations before they form swarms.

Current situation and forecast for locusts

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

Plague locust control

Controlling plague locusts can be difficult, especially 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. Control programs are most effective when landholders work together 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.

What support is available for landholders?

Our 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.

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.

How to control locust populations using chemical and biological controls

A range of control agents are available in NSW. Choosing the most appropriate control agent is determined by several factors, including where it is to be used (such as within a crop, pasture, stock or sensitive site scenarios), withholding periods and environmental considerations.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) is the regulator of agriculture and veterinary chemical products. All chemical products, including pesticides, used across the agricultural industry must be registered or permitted for use by the APVMA. Once a product is registered, it is approved for the uses listed on the product label. Other important factors such as PPE, storage and transport considerations are also included. For information on product labels, including a booklet on understanding pesticide chemical labels, please visit the APVMA website.

An insecticide is a form of pesticide. Other pesticides include herbicides and fungicides. There are many products with different trade names that contain the same active ingredient. Common insecticides used for locust control include those that contain the active ingredient additives of fenitrothion, fipronil and chlorpyrifos.

Fenitrothion is registered for use against locusts on pasture and a wide range of cereal and other crops. It is available as emulsifiable concentrate (EC) for ground control and as an ultra-low volume (ULV) formulation for aerial control.
Fipronil, also a ULV formulation for aerial control, is suitable for pasture and sorghum situations. Fipronil is not a 'knockdown' insecticide.
Chlorpyrifos is suitable for EC ground control only in crop or pasture situations.
Chlorpyrifosis suitable for EC ground control only in crop or pasture situations. LLS currently holds permit 88554 for the use of Country Chlorpyrifos for the control of locusts in certain situations. This permit is accessible via the APVMA website. Landholders should note that the APVMA’s final determination of the use of Chlorpyrifos was released on the 3 October 2024. Read the special gazette. Ultimately, the use of Chlorpyrifos for locust control will be phased out over the next year.
Malathion is registered for use against locusts. Malathion is available in an emulsion-in-water (EW) formulation and is available for use in cereals, non-crop, and pasture locations.

Dependent on the situation and availability, other insecticides may be used during a control campaign.

Alternatively, metarhizium, sold as Green Guard®, is a biological control agent which can be used in environmentally sensitive areas and areas of organic farming or chemical sensitivity. The agent is derived from a naturally occurring Australian fungus (Metarhizium anisopliae) that attacks locusts. Green Guard® can take 8 to 18 days to have an effect so should only be used to treat immature locusts, early in their lifecycle. It is not suitable for treating adult locusts. No withholding periods and/or slaughter intervals apply when using Green Guard®.

Always read the product label, SDSs (Safety Data Sheet) and any other permit (if relevant) relating to the product you have chosen to use.

Smaller holdings or house blocks that are ineligible to receive the above chemicals can source suitable domestic locust control chemicals from their local rural supplier or hardware store.

Chemical use qualifications

All persons using pesticides as part of their work must complete and maintain chemical accreditation training, in accordance with the NSW Pesticide Regulations (2017). More information is located on the NSW EPA website or you can talk to your local Biosecurity Officer for local course information.

Equipment

Always read the product label to ensure that suitable spraying equipment is used with that chemical. Most types of spray equipment can be used to treat nymph bands. Correctly calibrated boom sprays are the most suitable equipment. Boomless jets which can apply 50 to 200 litres per hectare can also be used.

Recording chemical use

The Pesticides Act 1999, requires that all chemical applications be recorded, including those chemicals applied for locust control. These records are to be kept for at least 3 years and are auditable by the EPA. For more information refer to the EPA website.

Withholding periods

Withholding periods must be observed to avoid residue issues. The actual withholding period, which differs depending on the control agent used, is provided on the insecticide label. For more information regarding withholding periods refer to the APVMA page and SafeMeat.

Buffer (no spray) zones

To reduce adverse environmental impacts from chemicals, buffer zones may be required for application adjacent to and upwind of environmentally sensitive areas. These sensitive areas include, but are not limited to, natural streams, rivers and watercourses, tanks and dams, waterways, beehives, human dwellings and neighbouring properties. Ensure that all buffer zones are established according to the label before spraying and adhere to all other label directions.

Aerial application

When contracting aerial applications, ensure that only EPA licensed aerial applicators are used. Under the Pesticides Act 1999, all those involved in decision-making about chemical application share the legal responsibility and may be fined if the chemical is misused. Misuse can include non-adherence to a buffer zone and damage, such as from off-target drift.

Clean-up after spraying

Empty all chemical containers and dispose of unused and waste materials in an environmentally responsible manner, in accordance with the label instructions of the chemical.

When rinsing, the PPE specified on the label for preparing spray and using prepared spray must also be worn. This is because the chemical remaining in a container is the concentrate and most toxic form of the chemical, even though it may be diluted during the rinsing process.

Rinsing is most effective while the contents are still moist inside. The longer residues have to dry and cake on the inside of containers, the more difficult they are to remove. If rinsing is carried out during mixing and loading, the rinsate can be emptied into the spray or mixing tank of the application equipment.

Disposal of rinsate or dilute chemical

It is best practice to use all the spray that has been mixed to treat locusts. To dispose of unused chemicals, first dilute and then dispose of in an environmentally responsible manner, such as in a disposal pit. Always follow the label instructions when carrying out this procedure.

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.