Migratory locust

Native to Australia, the migratory locust is a large, heavily built insect. Its colour ranges from green or brown when solitary to straw-coloured when swarming.

Migratory locusts are the world’s most widespread locust species, and are found throughout Africa, Asia and Australia. In Australia, they are found primarily in Queensland’s Central Highlands, though smaller populations are found as far south as northern New South Wales. Swarms of migratory locusts damage pasture and crops.

Migratory locust is not a prohibited or restricted invasive animal under the Biosecurity Act 2014.

Scientific name

Locusta migratoria

Description

  • Large, heavily built locust with adult body 14-60mm long.
  • Adults vary from green to brown in ordinary circumstances to straw-coloured when swarming.
  • Nymphs can be dark or striking black and tan.
  • Adults have fine hair on chest.
  • Adult flight is strong and steady, with slight green tinge visible on wing.

Distribution in Queensland

  • Confined mostly to Queensland's Central Highlands, with smaller populations further south.
  • See the Locusts fact sheet (PDF, 6MB) for distribution maps.

Life cycle

  • Nymphs and adults can be found year-round.
  • Damaging populations are restricted to warmer months.
  • In normal summer temperatures, minimum life cycle is:
    • eggs hatch after 11 days, producing nymphs
    • nymphs then take 30 days to become immature adults
    • immature adults take further 14 days to mature and lay eggs.

Crops affected

  • Sorghum, sugar cane, forage, wheat crops.

Impacts

Economic

  • Damages pasture and crops.
  • Avoid losses by planting less susceptible crops such as sunflower, chickpea, safflower and cotton.

Natural enemies

  • Birds, mammals, insects.

Control measures

  • Readily controlled with insecticides if treated at right time.
  • Different chemicals are used to control each locust species.
    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. Migratory locusts readily form nymph bands, which can best be seen early morning and late afternoon from the air or from 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 agricultural chemicals, you must read and follow all product label instructions.
  • 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 for up to 2 weeks after 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.

Legal requirements

  • Migratory 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.

More information