Current Locust Situation and News

Locust Situation 16 May 2014

This page summarises the known distribution of locusts during April-May and provides a brief outlook to spring 2014.

The next Locust Bulletin will be produced in October 2014.

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Australian Plague Locust (Chortoicetes terminifera)

Fledging of nymphs produced after the widespread rainfall during February and March resulted in moderate overall increases in adult population levels in all regions during April, and further increases in May. Localised high density adults were identified in parts of Southwest South and Central Queensland from mid-April to mid-May, with swarm densities recorded at a few locations. Occasional low density nymphs were identified in several regions of Queensland and New South Wales, along with medium density late instar nymphs and fledgling adults at some locations, indicating widespread, mostly low density egg laying occurred in the second half of February, continuing sporadically during March.

In New South Wales, surveys of the Central West, Riverina, Far West and Far Southwest regions identified a moderate increase in adult numbers to medium densities during April, while densities remained low in the Northwest Plains region. Occasional low density late instar nymphs were associated with higher density adults in the Far Southwest and Central West. High density young adults and some late instar nymphs were identified along the Queensland border north of Tibooburra. Surveys and reports from the Riverina also indicate an increase in locust numbers, with high density adults reported near Oaklands and medium density egg laying likely in the Narrandera area.

In Queensland, early April surveys identified mostly low density adults and occasional low density nymphs in the Southwest, Northwest and Central West regions, but mid-instar nymphs were detected at numerous locations in the Quilpie–Thylungra, Windorah and Eromanga areas in the Southwest. Fledging of nymphs produced a significant population increase in Southwest Queensland and in early May high density young adults, up to swarm density recorded at one location, developed in Barcoo Shire, extending over 50 km east and west of Windorah. Medium density adults and some nymphs were also recorded in Quilpie and Bulloo Shires. Population densities remained low in other regions, but increased in the Roma area in May.

Surveys were conducted in parts of the Far North, Northeast and Murray Valley regions of South Australia in late April. Isolated–Scattered density adults were identified in the Innamincka–Cordillo Downs area, but few locusts were detected in the Yunta–Burra or Morgan–Renmark area.

A small increase in overall locust numbers occurred in northern Victoria, primarily from local breeding. There was a report of medium density adults near Annuello in Northwest Victoria in early May, near where nymphs had been reported at the end of March.

The outlook for the rest of May and June is for medium density adults to persist in some regions of Queensland, New South Wales and Northwest Victoria, declining to low levels during June. The majority of eggs laid in March and April will diapause during winter, while those laid in May will develop, but will also mostly hatch in spring within weeks of diapause eggs. The outlook for spring is for a widespread low density nymphal generation in parts of the Central West, Riverina, Far West and Far Southwest regions of New South Wales, with the possibility of high density nymphs in localised areas. For Queensland a low–medium density nymphal generation could be produced from August in the Southwest region, but survival will depend on any winter or spring rainfall. Sporadic autumn egg laying in other regions of Queensland could produce some low density nymphs in late winter or spring. The nymphal population during spring will be larger than those of the previous two years and landholders are encouraged to report any hatchings, but the risk of widespread infestations remains low.

Spur–throated Locust (Austracris guttulosa)

Surveys in Queensland during April and May identified a further small increase in adult numbers in parts of the Central West and Northwest regions, along with residual low density nymphs in a few locations. Despite fledging of nymphs from the summer breeding season, adult numbers remained mostly at Isolated–Scattered densities in these regions, with Numerous density in a few locations. Only occasional adults were identified in Southwest Queensland, apart from Numerous density at one location south of Windorah. Very few adults were detected in South Central Queensland, New South Wales or South Australia. Survey of part of the Queensland Central Highlands in mid-May identified Isolated–Scattered density adults.

The low numbers and relatively late appearance of nymphs during 2013-14 indicates a restricted period of breeding in most regions during summer. The current population level remains below the average identified in previous years. There is a low risk of a significant infestation developing during 2014.

Migratory Locust (Locusta migratoria)

Surveys during April did not detect this species, but in mid-May Isolated and Scattered density adults were identified at several locations in the Emerald–Planet Downs–Arcadia Valley area in the Queensland Central Highlands. Although at low densities in the southern Central Highlands, populations can breed throughout the year in Queensland and some increase is therefore possible during winter and spring. Gregarisation can occur at local scales, often associated with cropping in eastern Queensland, and can therefore be difficult to detect without intensive surveys. However, the risk of any widespread infestation developing in 2014 remains low.

Map of locust forecasting regions mentioned on this web page

Map of locust forecasting regions
Circles indicate locations of APLC light traps.

Shaded areas indicate potential locust habitat areas.