Spur-throated locust

Native to Australia, the spur-throated locust can be readily distinguished from other locusts and grasshoppers by its large size and by the spur between its front legs.

Plagues of spur-throated locusts are less frequent than other locust plagues, but migrations to cropping areas can occur. Locust swarms can consume crops, pasture and trees. The most significant recent outbreak was in central western Queensland in 2010, when Biosecurity Queensland successfully prevented spur-throated locust swarms from migrating east to the Central Highlands and Maranoa cropping districts.

The spur-throated locust is not a prohibited or restricted invasive animal under the Biosecurity Act 2014.

Scientific name

Austracris guttulosa

Description

  • Nymphs and adults have a conspicuous spur between their front legs.
  • Nymphs are green on hatching, with a black stripe developing down their back as they grow.
  • Adults have slim, pale brown bodies, with a long straw-coloured stripe.
  • Hind wings are clear with a slight blue tinge.
  • Hind legs bear 2 rows of dark-tipped white spines.
  • Adults are 50-80mm long.

Habitat

  • Invades cropping areas, particularly the Central Highlands.

Distribution

Life cycle

  • Has 1 generation per year, taking several years to build up to plague densities.
  • Lays eggs October-February.
  • Eggs hatch within 18-30 days.
  • Nymphs develop over 47-90 days.
  • Swarms are formed by immature adults during winter.
  • Rainfall triggers dispersal of mature adults during spring and summer following overwintering period.

Crops affected

  • Summer crops, pastures, trees, sorghum, cotton.

Impacts

Economic

  • Forms dense swarms that feed on winter crops, pasture and trees.
  • Nymphs also cause significant crop damage, particularly in seedling sorghum.
  • Can have large impact on crops, even at low densities.

Natural enemies

  • Insectivorous birds and mammals, predator insects, parasites and diseases.

Control

  • Nymphs of this species do not form bands, making control of large, dispersed adult populations difficult through summer.
  • Readily controlled with insecticides during winter if swarms are detected and treated.
  • Different insecticides can be used to control each locust species.
  • Residues of some insecticides have negative effects on trade in agricultural products.
  • Only insecticides registered or approved for use to control spur-throated locust by the Australian Pesticides and Veterinary Medicines Authority can be used in Queensland's cropping or livestock producing areas.
  • Control of the spur-throated locust is a landholder's responsibility.
  • Biosecurity Queensland is responsible for recommending and coordinating locust control throughout Queensland.
  • The Australian Plague Locust Commission implements control measures when locusts reach sufficient numbers to present a threat to 2 or more states.
  • Appropriate application methods for the insecticides used to control locusts vary with the locusts' life stages and behaviour.

Insecticide control

Fledged and flying locusts - aerial spraying
  • Once locusts have fledged or are flying, aerial spraying of agricultural chemicals is the only efficient control method.
  • The aerial application of agricultural insecticides is a regulated activity under the Agricultural Chemical Distribution Control Act 1966.
  • Aerial spraying should be undertaken by a licensed aerial distribution contractor. Pilots in command of aircraft must hold a current pilot chemical rating licence.

Legal requirements

  • The spur-throated 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 animals under their control.
  • Local governments must have a biosecurity plan that covers invasive animals in their area. This plan may include actions to be taken for spur-throated locusts. Some of these actions may be required under local laws. Contact your local government for more information.

Further information