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Australian plague locusts

The Australian Plague Locust (Chortoicetes terminifera) is a native Australian insect. It occurs naturally in the far north west of NSW and adjacent areas of Queensland and SA, an area known as the channel country. It is a pest of pastures, field crops, and vegetables in NSW and southern Queensland, and infrequently in SA and Victoria. It also occurs in WA.

Scientist, Malcolm Campbell (Victoria DPI), says it is impossible to accurately predict where, or how extensive the locust problem will be this spring, but it is likely that some hatchings will occur in areas that were infested last season.

The Victorian Department of Primary Industries encourage sightings of locust activity to be reported to the Locust Reporting Line on 1300 135 559. Two reports of the Australian Plague Locust have recently been confirmed at Gunbower Island in the Northern Country, Victoria. Both infestations are small and not very dense. No egg hatching has been reported at Swifts Creek, where locusts were sprayed by Victoria DPI earlier this year. Overnight temperatures have been low throughout most of October, which may have delayed hatching.

Australian Plague Locusts are similar in appearance to grasshoppers. They can be identified by the large dark spot on the tip of the hind wings and the distinctive red shanks on the hind leg. The body colour varies; it can be grey, brown or green. Male locusts are 25-30 mm long while females are 30-42 mm long.  

The eggs of the locust hatch into very small ‘hoppers’ which can move short distances but cannot fly as their wings are underdeveloped. Like all insects, the locust develops through discrete stages called instars until becoming an adult. Only the adult Australian Plague Locust can fly.

When the locust is present in small numbers it behaves as a solitary insect and causes little or no damage, feeding primarily on summer grasses. When numbers increase, it can become gregarious and form very dense bands of hoppers or swarms of adults. Swarms initially form in the channel country and generally head south on hot northerly winds. These swarms usually land in central NSW where, given favourable conditions, they can breed, giving rise to new swarms which can fly south into the Riverina of NSW or into northern Victoria.

It is critical that growers act now and inspect paddocks in known locust areas. Malcolm says that a swift control response in Victoria could effectively end the locusts’ breeding cycle, ridding the state of the plague which entered from NSW two years ago.

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