Locust Bulletin January 2018

​​​​​​​ISSN 2204-9851

The Locust Bulletin is produced each month during the spring—autumn period and includes a general summary for each major locust species, details of known distributions with regional forecasts and maps of locust distributions.

Download

DocumentPagesFile size
Locust Bulletin January 2018 PDF10684 KB

If you have difficulty accessing these files, visit web accessibility for assistance.

Online version

General situation in December 2017 and outlook to March 2018

[expand all]

Australian plague locust - Chortoicetes terminifera

Locust densities remained low in all surveyed regions during December. The very low population levels identified during spring have continued, despite rainfall producing more favourable habitat conditions in many areas. Low numbers of locusts were recorded in the Central West, Far West and Far Southwest of New South Wales, Southwest and Central West Queensland, and in the Far North and Murray Valley regions of South Australia. Small increases in population density were detected in Central West and Far Southwest New South Wales, and in Central West Queensland.

In New South Wales, surveys of the Central West recorded low density adults, but locusts were more consistently distributed than in November.  Survey of the Far Southwest in mid-December identified occasional low density adults.

Surveys of Southwest Queensland in early December identified very few adults and no nymphs were detected. Survey in Central West Queensland in mid-December identified more consistent low density adults in the Longreach area.

In South Australia, limited surveys in December identified only occasional adult locusts in the Far North and Murray Valley regions.
Survey of Northwest Victoria in mid-December identified occasional low density adults.

Reports received by the Department of Primary Industries and Regional Development in Western Australia indicate that medium density adults persisted in several areas of the Central Agricultural Region during December.

The outlook for the remainder of summer is for population densities to remain generally low in most regions of inland eastern Australia. Localised breeding is likely to have occurred in habitat areas that received heavy rainfall in early December and this will result in small regional population increases during January. Many of those areas did not receive further significant rainfall during December, so nymph mortality may limit potential increases in some areas. Population increases are likely in the Central West, Far Southwest and Riverina regions of New South Wales and are possible in South Central and Central West Queensland.

Breeding is likely to continue during summer and autumn, but given the current low population level there is a low risk of widespread regional infestations developing during summer, and a very low risk of swarms affecting agricultural regions across several states in autumn. The probability of a late summer or autumn nymph generation, which could result in localised dense infestations, will depend on the distribution of rainfall during January and February. Seasonal rainfall forecast models suggest an above-average rainfall expectation over coming months and a sequence of heavy rainfall events could result in significant population increases in autumn.

4 January 2018

Spur-throated locust - Austracris guttulosa

There is a widespread low density population of adults in inland Queensland, with medium densities in the Northwest and Central West regions. Limited surveys in December identified consistent Isolated–Scattered density adults in Bulloo and Quilpie Shires of Southwest Queensland. Surveys in November recorded Scattered–Numerous density adults in the Richmond, McKinlay and Flinders Shires. Samples showed females were developing eggs. Occasional adults were recorded in the Far North and Northwest regions of South Australia and in the Northwest Plains and Far West New South Wales.

The Queensland Central Highlands has not been surveyed since September, when only low density adults were recorded, and adult densities are likely to have increased as a result of redistribution and aggregation. Rainfall in recent months, particularly in the Queensland Central West, Central Highlands and South Central regions, created favourable habitat conditions for the commencement of breeding. Eggs laid in November will have commenced hatching during December and nymphs are likely to be recorded in several regions of Queensland during January and February. Females can lay multiple times during summer, usually following significant rainfall. Nymphs of this species do not aggregate to form cohesive bands, but can reach densities of 30/m2 in favourable habitats. Nymphs are susceptible to desiccation and mortality can increase in the absence of follow-up rainfall after hatching.

There is a low risk of swarms developing in or migrating to agricultural regions during summer. The likelihood of an overall population increase during 2018 compared to 2017 will depend on the distribution, frequency and persistence of rainfall during the northern wet season.

Migratory locust - Locusta migratoria

Previous surveys identified low numbers of adults at several locations south of Emerald in the Central Highlands and near Taroom in South Central Queensland. This species is common in these regions and rapid population increases are possible in favourable habitat.  Gregarious populations can occur at local scales and are often associated with forage or cereal cropping.

Heavy rainfall in the Central Highlands and South Central regions of Queensland over recent months produced suitable soil and vegetation conditions for breeding. Small gregarious populations could develop in localised areas of these regions during 2018. However, there is currently a low risk of a widespread infestation developing during summer or autumn.

It is important that any locust activity be reported as soon as possible to your local biosecurity authority, primary industries department or to the commission. A toll–free call to the APLC can be made on 1800 635 962. An answering machine is attached for after–hours calls. Reports can also be e–mailed to APLC or made through the internet at Australian Plague Locust Commission.

Locust distribution map – Chortoicetes terminifera

Map of Australian plague locust distribution 1 December to 31 December 2017 

 

Australian plague locust (Chortoicetes terminifera)

Situation in December 2017 and forecast to March 2018

New South Wales

[expand all]

Central West and Northwest Plains
Central West, Northwest and Central Tablelands Local Land Services

Locusts and conditions

  • The locust population remained at low densities during December.
  • Survey of the Central West Local Land Services (LLS) area in early December identified only Isolated–Scattered density adults in the Narromine–Tullamore–Condobolin area. Survey in mid-December identified Isolated–Scattered density adults in the Trangie–Tottenham–Nyngan area. No nymphs were detected, but adult  locusts were more consistently distributed than records from previous surveys, indicating a gradual population increase.
  • There was moderate–heavy rainfall (20–>40 mm) throughout Central West and Northwest LLS regions during the first week of December. There was light–moderate rainfall in parts of the Central West LLS during the last week of the month. Pasture vegetation became green in mid-December, but has commenced drying out in some areas.

Forecast

  • The widespread heavy rainfall in early December is likely to have initiated breeding in suitable habitats. Sporadic egg laying during December will produce a summer nymph generation, particularly in the southern Central West LLS. Hatchings could have commenced after mid-December and nymphs are likely to develop at Present–Numerous densities, resulting in a moderate increase in overall adult numbers to Numerous density in late January.
  • The likelihood of a large population increase in autumn as a result of a further generation developing in late summer will be primarily influenced by the distribution of rainfall during January and February.
  • There is a low probability of significant immigration from other regions during summer.

Risks

  • There is a low risk of a widespread infestation developing during summer or autumn.

Riverina
Riverina and Murray Local Land Services

Locusts and conditions

  • The regional locust population level is expected to have remained low during December.
  • Surveys in late November identified Isolated–Scattered density adults in the Hillston, Hay and Deniliquin districts. Only occasional Isolated density adults were recorded in other areas.
  • There was moderate–heavy rainfall (20–>40 mm) throughout the Riverina region during the first week of December, with falls >50 mm in many areas There was further patchy, light–moderate rainfall (<20-40 mm) during the last week of December. Pasture vegetation is green in many areas.

Forecast

  • Improved habitat conditions in the eastern Riverina and Murray LLS areas are likely to have initiated some low density breeding during December. Sporadic egg laying after the widespread heavy rainfall at the start of December would have produced nymphs, mostly at low densities, from late December. Habitat conditions have remained favourable for nymph survival in most areas.
  • Hatchings could continue during January as breeding adults redistributed to favourable habitat areas during December. Some medium or localised high density nymphs could develop during January. Fledging will follow from late January and is likely to result in a an overall increase in adult numbers to Scattered-Numerous densities during February.
  • Some low density immigration from adjacent areas of the Far Southwest was possible during December, and further localised egg laying could have occurred after rainfall in late December in the Hay–Maude area.
  • There is a low probability of significant immigration from other regions during summer or autumn.

Risks

  • There is a low risk of a widespread regional infestation developing during summer or autumn.

Far West and Far Southwest
Western Local Land Services

Locusts and conditions

  • Locust population levels remained generally low in these regions during December.
  • Surveys of the Broken Hill, Tibooburra and Wanaaring districts in early December identified only occasional Isolated density adults. No nymphs were detected.
  • Survey of the Far Southwest region in mid-December identified Isolated density adults in the Wentworth, Lake Victoria and Pooncarie areas. Scattered density adults were recorded in the Ivanhoe area in late November.
  • The Fowlers Gap and White Cliffs light traps recorded no locusts during December.
  • There was moderate–heavy rainfall (20->40 mm) throughout the Far Southwest region and in the Wanaaring, Bourke, Wilcannia, Cobar and Brewarrina districts of the Far West during the first week of December. Pasture vegetation remains green in some parts of the Far Southwest, but is becoming dry in most other areas.

Forecast

  • Improved habitat conditions during late November and December is likely to have initiated some localised, low density breeding in parts of the Far Southwest region. No nymphs were detected in the Wentworth area during December, so any hatching from November breeding is likely to have been at low densities. However, habitat conditions remained favourable for nymph survival during December. Any egg laying following early December rains would have produced nymphs at the end of the month. Given the low background population level, nymphs are likely to develop mostly at low densities during January.
  • Medium density nymphs could develop in some areas of the Far Southwest as a result of aggregation of breeding adults in favourable habitats.
  • Fledging of nymphs developing from eggs laid in December will occur in late January and could result in an overall increase in adult numbers to Numerous density during February.
  • The likelihood of a large population increase as a result of a generation developing in early autumn will be primarily influenced by the distribution of rainfall during February. Without at least moderate rainfall, dry habitat conditions will limit breeding and increase the rate of nymph mortality.
  • There is a low probability of any significant immigration from other regions during summer.

Risks

  • There is a low risk of widespread regional infestations developing during summer or autumn.

All locust activity should be reported to your Local Land Services or the Department of Primary Industries, NSW. A toll-free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls. Reports can also be e–mailed to APLC or sent through the web page at Australian Plague Locust Commission.

Queensland

[expand all]

Southwest
Barcoo, Bulloo, Quilpie and Diamantina Shire

Locusts and conditions

  • The locust population level remained very low during December. There were no reports of locust activity.
  • Bulloo and Quilpie Shires were surveyed in early December. Only occasional adult locusts were recorded and no nymphs were detected.
  • The Birdsville and Nooyeah Downs light traps did not record any locusts during December.
  • There was localised light–moderate storm rainfall (<20-40 mm) in parts of Bulloo Shire during the first week of December, and in Barcoo Shire in mid-December. Pasture vegetation is dry in most areas.

Forecast

  • Habitat conditions remain largely unfavourable for locust breeding. Given the very low population densities recorded, any eggs laid during January or February are likely to produce only low density nymphs.
  • There is a low probability of a significant population increase in late summer or autumn.
  • There is a low probability of immigration from other regions during January or February.

Risks

  • There is a low risk of a widespread infestation developing during summer or autumn.

Central West & Northwest
Longreach, Barcaldine and Blackall-Tambo Regional Council. Boulia, Cloncurry, Flinders, Mckinlay, Mt Isa, Richmond and Winton Shire

Locusts and conditions

  • The locust population level remained low in areas surveyed during December. There were no reports.
  • Survey of the Longreach Regional Council (RC) area in mid-December identified Isolated–Scattered density adults to the west of Longreach. No nymphs were detected.
  • The Longreach light trap recorded no locusts during December.
  • There was light–moderate localised storm rainfall (<20-40 mm) in Flinders Shire, and in Barcaldine and Blackall-Tambo RC areas during the first week of December.

Forecast

  • Locust population levels are expected to remain generally low in these regions during January and February. However, the consistent locust counts recorded near Longreach area suggests a small increase in population numbers, and may reflect a more widespread increase in the region.
  • Rainfall in early December produced suitable habitat for localised breeding in parts of Barcaldine and Blackall-Tambo RC areas. Any resulting nymphs would have hatched during the second half of December and will fledge in late January. A moderate increase in adult numbers to Scattered–Numerous densities is likely in some areas during February.
  • There is a low probability of any immigration from other regions during January or February.

Risks

  • There is a low risk of widespread regional infestations developing during summer or autumn.

Central Highlands
Central Highlands and Isaac Regional Council

Locusts and conditions

  • Locust population densities are expected to have remained generally low during December. There were no reports.
  • There was light–moderate storm rainfall (<20-40 mm) throughout the region during the first week of December and further localised light–moderate falls in Central Highlands RC area during the last week of December. Vegetation conditions are variable, with some areas of the Central Highlands RC area remaining green.

Forecast

  • Rainfall in November and December has maintained suitable soil and vegetation conditions for locust breeding, particularly in Central Highlands RC area and in Banana Shire.
  • Localised breeding could have produced nymphs in some areas. Fledging during January and February could result in localised increases in population to Scattered–Numerous densities.
  • There is a low probability of immigration from other regions during summer or autumn.

Risks

  • There is a low risk of a widespread infestation developing during summer or autumn.

South Central & Darling Downs
Balonne, Murweh and Paroo Shire. Maranoa, Western Downs and Goondiwindi Regional Council

Locusts and conditions

  • Locust population level is expected to have remained generally low during December. There were no reports of locust activity.
  • There was light–moderate storm rainfall (<20-40 mm) in Paroo and Balonne Shires, and in Maranoa RC area, during the first week of December. There was light–moderate rainfall in Western Downs RC during the last week of December. Pasture vegetation is green in many areas.

Forecast

  • Locust population levels are likely to remain generally low during January and February. However, localised breeding in response to the heavy rainfall in recent months could have produced nymphs in some areas during December. Fledging during January could result in localised increases in adult numbers to Scattered–Numerous density.
  • There is a low probability of significant immigration from other regions during summer.

Risks

  • There is a low risk of a widespread regional infestation developing during summer or autumn.

Locust activity should be reported to Biosecurity Queensland (Queensland Department of Agriculture and Fisheries) on 132 523. A toll free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls. Reports can also be e–mailed to APLC or sent through the web page at Australian Plague Locust Commission.

South Australia

[expand all]

Far North, Northeast, Northwest & Western Agricultural Region

Locusts and conditions

  • Locust population levels are likely to have remained very low in these regions during December as residual green vegetation dried out..
  • No locusts were recorded during limited survey of the Innamincka area of the Far North in early December.
  • The Dulkaninna and Oodnadatta light traps recorded no locusts during December.
  • There was light–moderate rainfall (<20–40 mm) in parts of the Northeast and Western Agricultural regions during the first week of December. There was further light-moderate rainfall in parts of the Northwest and Western Agricultural regions during the last week of December.

Forecast

  • The population level is likely to remain generally low in these regions during January and February. The very low population level identified over recent months and the absence of higher densities in other states limits the possibility of significant breeding or immigration. However, higher population numbers could have developed further west in South Australia following frequent rainfall events and migrations from those areas could contribute to the summer breeding population in the Northwest, Western Agricultural or Far North region.
  • Some limited low density breeding was possible in areas that received moderate rainfall in early December. Only low density nymphs are likely to have developed and would maintain the overall background population level in January.
  • There is a low probability of significant migrations into these regions during summer.

Risks

  • There is a low risk of widespread regional infestations developing in summer or autumn.

Murray Valley, Mt Lofty Ranges & Southeast Region

Locusts and conditions

  • Locust densities remained low during December.
  • Limited survey of the Murray Valley region in mid-December identified occasional Isolated density adults.
  • There was widespread light–moderate rainfall (<20–40 mm) in these regions during the first week of December.

Forecast

  • Locust population levels are likely to remain low during summer and autumn.
  • There is low probability of any significant immigration during January and February.

Risks

  • There is a low risk of a widespread infestation developing during summer or autumn.

Locust activity should be reported to Biosecurity SA (Primary Industries and Region South Australia) on the Locust Reporting Hotline on 1300 666 101. A toll-free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls. Reports can also be e–mailed to APLC or sent through the web page at Australian Plague Locust Commission.

Victoria

[expand all]

North West & North Central Victoria

Locusts and conditions

  • Locust population levels remained low in Victoria during December.
  • APLC survey in the Northwest region in mid-December identified occasional Isolated density adults in the Mildura–Ouyen–Murrayville area. No nymphs were detected.
  • There were unconfirmed reports of locusts from landholders in the Swifts Creek area of Gippsland during December.
  • There was widespread moderate–heavy rainfall (20–>40 mm) throughout these regions during the first week of December, and further light–moderate falls in eastern North Central Victoria during the last week of the month.

Forecast

  • Habitat conditions became favourable for locust breeding in Northwest and North Central Victoria during December. Sporadic, low density egg laying could have continued throughout the month. Localised low density nymphs are likely to develop during January but are only likely to contribute to a small increase in adult numbers in February.
  • There is a low probability of any significant immigration during summer.

Risks

  • There is a low risk of a widespread infestation developing during summer or autumn.

Locust activity should be reported to Department of Economic Development, Jobs, Transport and Resources on 1300 135559. A toll-free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls. Reports can also be e–mailed to APLC or sent through the web page at Australian Plague Locust Commission.

[expand all]

Glossary of locust terms and density categories used in the Locust Bulletin

Locust biology and behaviour

TermDefinition
adultA fully winged, mature locust capable of breeding and migrating
bandDense aggregation of nymphs, usually moving forward together
diapausePeriod of dormancy in anticipation of unfavourable environmental conditions
egg bedAn area of soil containing many egg pods (up to 1000 per square metre)
fledgeFinal nymphal moult to a soft-bodied adult incapable of long-distance flight
instarDiscrete stages of nymphal development each separated by a moult
layingFemale locusts each depositing clutches of 20-60 eggs into the ground in froth-lined egg pods
nymphJuvenile wingless locust. Often referred to as the hopper stage
swarmDense aggregation of adults, milling at the same spot or flying closely together

Locust density categories

Where higher densities occur, a large proportion of the regional population is concentrated in very small areas with lower densities elsewhere, so the higher densities cannot be extrapolated over the area of an entire region. A range of density classes is usually found within a surveyed region.

Nymph DensitiesNumber per m2
Present1 – 5
Numerous6 – 30
Sub–band31 – 80
Band> 80
Adult DensitiesNumber per m2Number per hectare
Isolated– 0.02< 200
Scattered0.03 – 0.1> 200 – 1000
Numerous0.2 – 0.5> 1000 – 5000
Concentration0.6 – 3.0> 5000 – 30,000
Low Density Swarm4.0 – 10> 30,000 – 100,000
Medium Density Swarm11 – 50> 100,000 – 500,000
High Density Swarm> 50> 500,000
General density classesNymph densitiesAdult densities
very low, occasionalNil–PresentNil–Isolated
lowPresentIsolated–Scattered
mediumNumerous—Sub–bandScattered–Numerous
highBandsConcentration–Swarms

Reporting locust infestations

It is important that all locust activity is reported as soon as possible to your nearest state agriculture agency office or to the Australian Plague Locust Commission.

StateAuthority for reporting locusts
New South WalesLocal Land Services (LLS) or Department of Primary Industries
QueenslandBiosecurity Queensland, Department of Agriculture and Fisheries
South AustraliaBiosecurity SA, Primary Industries & Regions South Australia (PIRSA)
VictoriaBiosecurity Agriculture, Department of Economic Development, Jobs, Transport and Resources

Reports to the Australian Plague Locust Commission can be made by:

Free call (Canberra): 1800 635 962 (24 hours)
Fax (Canberra): (02) 6272 5074
E–mail: APLC
Internet: Australian Plague Locust Commission

​​​​​​