Australian plague locust
© Queensland Government
Native to Australia, the Australian plague locust is a grey, brown or occasionally green insect that can attack and destroy crops and pastures. Of all locusts in Queensland, it has the greatest economic impact because of the extent and frequency of outbreaks.
This species breeds successfully after good rains in the Channel Country of western Queensland. Locusts then migrate on prevailing weather systems to invade adjacent agricultural areas, including those in southern Queensland. A high-density swarm covering 2km2 can eat 20t of vegetation per day.
The Australian plague locust is not a prohibited or restricted invasive animal under the Biosecurity Act 2014.
- Locust with body colour ranging from grey to brown or occasionally green.
- Adults are 25-44mm long.
- Hind wing is clear with conspicuous black smudge at tip.
- Hind legs have red shanks.
- Makes short flights just above grass.
- Often lands side-on to observer.
- Breeding occurs after good rains in Channel Country of western Queensland.
- Locusts then migrate on prevailing weather systems to invade adjacent agricultural areas (including southern Queensland).
Distribution in Queensland
- Nymphs can form dense bands of up to 5,000 locusts per m2.
- See the Locusts fact sheet (PDF, 2MB) for distribution maps.
- Swarms of flying adults occur spring-autumn.
- Up to 4 generations occur each year.
- Eggs can survive extended dry periods.
- In normal summer temperatures, minimum life cycle is:
- egg: 11 days
- nymph: 35 days
- laying adult: 12 days.
- Summer crops, cereal crops, vegetables, orchards, forage crops, pastures.
- Damages crops and pastures.
- A high-density swarm (more than 50 insects per m2) of Australian plague locusts covering 2km2 will contain around 1 billion insects, which can eat 20t of vegetation a day. Locusts at both nymph and adult stage can cause extensive crop and pasture damage. Summer crops are most at risk in Queensland, but all crops can be attacked.
- Locusts' ability to invade previously uninfested areas and lay eggs within days, combined with the mobility of flying swarms, makes swarm control particularly difficult for individual landholders.
- Birds, mammals, insects.
- Readily controlled with insecticides if treated while in nymph stage.
- Different chemicals are used to control each locust species.
- Only insecticides registered or approved for use by the Australian Pesticides and Veterinary Medicines Authority are recommended for use.
- Biosecurity Queensland is responsible for recommending and coordinating control strategies in Queensland. The Australian Plague Locust Commission implements control measures when locusts reach sufficient numbers to present a threat to two or more states.
- Appropriate application methods for chemicals to control locusts vary with locusts' life stage and behaviour.
Nymphs – ground spraying
- Nymph bands are the best targets for ground spraying using agricultural chemicals. Australian plague locusts readily form nymph bands, which can be best seen early morning and late afternoon from the air or raised areas.
- Large nymph bands can be sprayed with boom sprays. Isolated and small areas can be sprayed using misting machines or knapsack sprayers.
- No licence is required to control locusts on your own property using insecticides from ground-spraying equipment.
- When using insecticides, you must read and follow entire label directions.
- Although all bands are worthy of control, best results are achieved if control is undertaken when nymphs are in smallest area.
- Factors influencing movement of nymph bands and effectiveness of control include nymph density, weather and cover.
- Nymphs at densities below 30 insects per m2 move very little and don't form bands.
- Spraying in the late afternoon is most effective, as nymphs tend to spread out during the day. Strong winds may cause nymphs to shelter in cracks in ground or behind windbreaks.
- Dense, high pasture or crops should not be sprayed in still conditions, as wind turbulence is needed for spray to penetrate foliage.
- Nymphs die after contact with, or ingestion of, treated vegetation. This may be 2-48 hours after spraying. Follow-up treatments may be necessary after initial spraying, as several waves of bands will hatch from 1 egg bed.
Fledged and flying locusts – aerial spraying
- Once locusts have fledged or are flying, aerial spraying with agricultural chemicals is the only efficient control method.
- Aerial spraying should be undertaken by licensed aerial distribution contractor. Pilot in command of aircraft must hold current pilot chemical rating licence.
- The Australian plague locust is not a prohibited or restricted invasive animal under the Biosecurity Act 2014. However, by law, everyone has a general biosecurity obligation (GBO) to take reasonable and practical steps to minimise the risks associated with invasive plants and animals under their control.
- Local governments must have a biosecurity plan that covers invasive plants and animals in their area. This plan may include actions to be taken on certain species. Some of these actions may be required under local laws. Contact your local government for more information.
- Last reviewed: 18 Apr 2016
- Last updated: 15 Jun 2016