Australian plague locust situation update

Australian plague locusts (Chortoicetes terminifera) are native insects that, if left unmanaged, pose a serious threat to pastures, crops and horticulture. While its native range is in Queensland and New South Wales, outbreaks can intermittently occur in Victoria.

Situation update: June 2026, outlook to spring

Victoria

The overall outlook for the Mallee region is a moderate to high probability of high numbers of nymphs developing and migrations occurring, whilst the Wimmera region can expect low to moderate probability of high numbers of nymphs developing in spring. Prepare your chemicals and management approaches.

Agriculture Victoria joined forces with the Australian Plague Locust Commission and conducted ground surveys in north-west Victoria in mid-May following reports of high locust activity in late April. Consistent low to medium densities of adult locusts were found.

Most of the sampled adult females were observed with eggs developing or signs of egg-laying occurring, although widespread egg laying could not be confirmed.

Above average rainfall in May in north-west Victoria means that some habitats should remain favourable for locust breeding with adequate soil moisture for eggs to develop. This is despite the BOM forecast for below average rainfall and warmer winter temperatures from a developing El Niño. Eggs are predicted to hatch in spring in Victoria from late September onwards, likely resulting in some high densities of nymphs.

Eastern Australia

The locust population increased substantially in autumn from previously low background levels to medium to high levels in inland eastern Australia. Favourable habitat was established following heavy rainfall in February and March while warm autumn weather encouraged southward and south-eastern migrations. April rainfall was low but above average rainfall in May but contributed to suitable conditions for continued locust breeding.

The overall outlook is for some medium to high densities of nymphs hatching in the southern part of inland eastern Australia and a moderate to high likelihood of widespread infestation developing in spring.

Who is responsible for managing locusts?

In Victoria, the government, private landholders, public land managers and the community all have a role to play in managing locust populations and minimising their impact.

All landholders and land managers are responsible for reporting and managing locusts on their land.

Agriculture Victoria undertakes surveillance and works closely with all stakeholders to provide relevant, timely and accurate information on locust populations and movements throughout the season.

Victoria is a member of the Australian Plague Locust Commission, a joint partnership between the Australian Government and the state governments of Victoria, New South Wales, Queensland and South Australia. The commission undertakes surveillance throughout south-eastern Australia and provides information on current and future locust activity.

Locust management strategies

Chemical insecticide ground spraying is the most successful way to manage locusts. The best time to control locusts is around 2 weeks after hatching when they are young and cannot fly (at the nymph stage). At this stage the young locusts (nymphs) are between 8 and 12 mm long and start to band together (Fig. 1).

Managing locusts can be difficult, especially at the adult stage when they are highly mobile and moving in swarms. Spraying eggs is also ineffective, as the eggs are laid well beneath the soil.

Diagram showing the locust life cycle from eggs to adult, including growth stages (instars), with early stages highlighted as targets for insecticide application.

For more information about various control options for the management of locusts, see Chemical use and crop residues

Further information

Visit Agriculture Victoria’s Australian plague locust online learning module page for a 20-minute interactive short learning course.

Reporting locusts

Please report locust activity on your property. Reporting helps Agriculture Victoria monitor locust activity across the state. The monitoring helps us produce accurate forecasts on locust activity, including timing of hatching and densities. Public and private land managers can use this information to pinpoint where and when to spray, to reduce overall numbers and help protect Victoria’s agriculture industry.