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Current Locust Situation and News
Locust situation in May 2009
This page summarises the known distribution of locusts during April 2009 and provides a brief outlook to spring 2009. The next Locust Bulletin will be published in spring 2009.
- Australian Plague Locust Situation
- Forecast development dates
- Spur-throated Locust Situation
- Migratory Locust Situation
Australian Plague Locust (Chortoicetes terminifera)
In the Nyngan–Coonamble area of Central West New South Wales and around Bourke hatching began in mid-March and many hopper bands developed by the end of the month. The APLC carried out some 6,500 ha of aerial control in these areas between 29 March and 6 April. The infestation in the Coonamble–Quambone area produced swarms after mid-April, despite control by landholders, Livestock Health and Pest Authorities (LHPAs) and the APLC. Swarms also developed in the Nyngan–Tullamore area in late April. The adult population has declined in the Tibooburra–Broken Hill and the Ivanhoe–Pooncarie areas of far western New South Wales, but egg laying has occurred in some areas. Following migration in late March in the Far North of South Australia there was a medium density adult population around the northern Flinders Ranges in mid-April, but by the end of the month only low density adults remained in this area.
The outlook for autumn is for the high density adult generation to persist during May in Central West New South Wales. The risk of long distance migration from this population is low, but some local movement into adjacent districts is possible. A further nymphal infestation in spring is likely in the Central West. Diapause eggs were laid near Parkes in the southern part of the region during March and April. A nymphal infestation is likely in spring in the Wilcannia–Broken Hill, Tibooburra–Packsaddle and Ivanhoe–Menindee areas in western New South Wales following high density egg laying in some locations in March and April. Localised egg laying is likely to have occurred in favourable habitats in the Far North region of South Australia.
In New South Wales high adult densities were recorded throughout the Central West during April, with swarms in the Nyngan–Tullamore and Coonamble–Quambone–Collie areas. Egg development was identified in late April, and some egg laying was reported in early May. Eggs layed in April and May will not hatch until spring, beginning in mid-September around Coonamble and in early October in the southern Central West. Although population appeared to decline in the Tibooburra–Broken Hill area, swarms remained around Milparinka and Broken Hill in mid-April and high density egg laying is likely to have occurred in these areas. Surveys in the Riverina indicate a residual low density population, with medium density adults in a few locations.
The population in western Queensland declined during April. Surveys in all regions identified low density adults with very few locusts in the Central Highlands and Central West. There is unlikely to be any population increase before October in Queensland.
Locust density remained low in northern Victoria during April, with small populations reported near Echuca and Tungamah.
In Western Australia medium–high density locusts were reported in a number of Shires the Central and Western Agricultural Regions during April. Breeding during autumn could produce a nymph infestation in spring.
Forecast development dates for indicative locations in NSW, Queensland and South Australia
Forecast dates in the table below are based on development models for possible egg laying for known adult populations and assuming sufficient soil moisture for direct development. Development dates are estimated from longterm average temperatures at these locations and variation in any laying dates is expected. Hatching time indicates the start of emergence of the nymphal population.
| Location - NSW | Egg laying | Hatching | Mid-instar | Fledging |
|---|---|---|---|---|
| Coonamble-Quambone | 1 May | 16 September | 1 October | 22 October |
| Peak Hill-Narromine | 24 March | 16 October | 29 October | 17 November |
| Bourke-Yantabulla | 20 March | 13 April | 28 April | 30 May |
| Bourke-Enngonia | 1 May | 1 September | 19 September | 11 October |
| Tibooburra-Wanaaring | 15 April | 25 August | 13 September | 5 October |
| Broken Hill - Wilcannia | 4 April | 30 August | 16 September | 8 October |
| Ivanhoe - Menindee* | 26 March | 17 September | 3 October | 24 October |
| Nyngan-Tullamore | 10 May | 26 September | 12 October | 31 October |
|
Location - Qld |
Egg laying | Hatching | Mid-instar | Fledging |
| Cunnamulla-Charleville* | 18 April | 13 August | 1 September | 25 September |
| Quilpie-Eromanga* | 18 April | 4 August | 23 August | 18 September |
|
Location - SA |
Egg laying | Hatching | Mid-instar | Fledging |
| Moolawatana-Marree | 15 April | 16 August | 6 September | 28 September |
| Hawker-Yunta | 15 April | 30 September | 21 October | 4 November |
* A proportion of the eggs laid at this time would enter diapause and hatch in spring, with some nymphal emergence during autumn.
Spur-throated Locust (Austracris guttulosa)
There is a widespread medium density adult population throughout Northwest, Central West and South Central Queensland and in the Northwest Plains of New South Wales, with Concentration density adults in Northwest and northern Central West Queensland. An increase in adult numbers in these regions is common during autumn, as fledging of nymphs completes recruitment of the adult population for this season. There is also likely to be a medium–high density population in the Queensland Gulf and parts of the Barkly Tableland at this time of year. Late instar nymphs were found in the Longreach area in mid-April, indicating breeding continued during February. Young adults often redistribute in autumn and form overwintering swarms, which may feed in green vegetation areas and roost in trees. Reports of occasional spur-throated locusts as far south as Melbourne during March and April indicate considerable migratory redistribution of immature adults during autumn.
There were consistent counts of Numerous and some Concentration density adults in the Winton and Longreach Shires in Queensland during April, with Isolated–Scattered density adults in Blackall-Tambo and Barcaldine Regional Council areas, Paroo Shire and in the Central Highlands and Southwest Queensland. In New South Wales Numerous density adults were also widespread in the Darling, Northwest and Central West Livestock Health and Pest Authority (LHPA) areas. The light trap at Longreach caught locusts in the first week of April, while catches continued throughout April at Julia Creek. This may reflect migratory activity of the young adult population in northwest Queensland. There was a report of local high density adults near Dysart in the Central Highlands, but surveys though this region identified Isolated–Scattered density adults in most areas.
Migratory Locust (Locusta migratoria)
Surveys during April identified very few adults of this species, with only occasional Isolated density adults to the west of Springsure in the Queensland Central Highlands. No surveys were conducted in the Darling Downs or the Northwest Plains of New South Wales, however, where low numbers were identified during March.
There were no catches of this species at the Longreach or Julia Creek light traps during April. Vegetation conditions are favourable for locust breeding in parts of South Central Queensland, the Central Highlands and the Darling Downs, where there is a potential for a continuing low level population.
5 May 2009