Locust Bulletin February 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 February 2018 PDF10620 KB

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

Online version

General situation in January and outlook to April 2018

[expand all]

Australian plague locust - Chortoicetes terminifera

The very low locust population level during spring continued in December and January. No high density locusts have been detected or reported, despite rainfall producing short-lived favourable habitat conditions in many areas. Low numbers of locusts were recorded in the Riverina, Far West and Far Southwest of New South Wales, and the Central West, South Central and Central Highlands regions of Queensland during January. Small increases in population density were detected in the Central Highlands and South Central regions of Queensland, where localised breeding occurred during December. Although some localised low density breeding is likely to have occurred in other regions areas during December and January, most habitats dried out rapidly and extreme temperatures are likely to have caused increased mortality of nymphs and adults.

In New South Wales, surveys of the Riverina and southern Central West regions recorded low density adults and no nymphs were detected.

In Queensland, surveys of the Central Highlands and parts of the Central West and South Central regions in mid-January recorded consistent counts of low density adults, along with occasional late instar nymphs in areas south of Emerald. There were also medium density populations of other grasshopper species in the Central Highlands.

No surveys were conducted in South Australia and no reports were received. Habitat conditions are dry in most regions and, based on previous surveys, locust population numbers are expected to have remained low.

No surveys were conducted in Victoria and most reports were of wingless grasshoppers, Phaulacridium vittatum. Locust population numbers are expected to have remained low.

Reports received by the Department of Primary Industries and Regional Development in Western Australia indicate that medium density adults were still present in part of the Central Agricultural Region during January.

The outlook for February and autumn is for population densities to remain generally low in most regions of inland eastern Australia. Breeding is likely to continue during February and autumn, but given the current low population level there is a low risk of widespread regional infestations developing, and a very low risk of swarms affecting any agricultural region during autumn. The probability of a significant autumn nymph generation has declined, although localised higher density populations could develop if widespread heavy rainfall occurs during February.

1 February 2018

Spur-throated locust - Austracris guttulosa

There is a widespread low density population of adults in inland Queensland. Surveys in January recorded Isolated–Scattered density adults, along with low density nymphs, at many locations south of Emerald in the Central Highlands and in the Roma–Mitchell area in the South Central region. Nymphs are likely to have developed in other areas of South Central Queensland and in parts of the Central West, Northwest and Gulf regions during January, following heavy rainfall in recent months. Dry habitat conditions will increase nymph mortality in Northwest and Central West Queensland. The survival of nymphs to fledging will be influenced by rainfall during February in Central West, Northwest and South Central Queensland. Further egg laying will also depend on the distribution of heavy rainfall during February and March.

Fledging of nymphs will commence in February, with the bulk of those from this season’s breeding fledging during March and April. Young adults will gradually replace the current breeding population, but large population increases are unlikely except in the Queensland Gulf and Central Highlands regions. The likelihood of an overall population increase during 2018 compared to 2017 has declined, but the distribution, frequency and persistence of rainfall during February and March could result in a significant late cohort of nymphs.

Migratory locust - Locusta migratoria

Low numbers of adults were identified in the Queensland Central Highlands and South Central regions during January. Isolated density adults were recorded at several locations in Central Highlands and Maranoa Regional Council areas and in Banana Shire, and Present density late instar nymphs at one location near Capella. 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.

Rainfall events in the Central Highlands and South Central regions of Queensland over recent months produced a sequence of suitable soil and vegetation conditions for breeding. Small gregarious populations could develop in localised areas during 2018. However, there is currently a low risk of a widespread infestation developing during 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 January to 31 January 2018 

 

Australian plague locust (Chortoicetes terminifera)

Situation in January and forecast to April 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 in surveyed areas during January. There were no reports.
  • Limited survey was conducted in the southern Central West Local Land Services (LLS) area and only isolated density adults were recorded in the Narromine–Tullamore–Trundle–Condobolin district. No nymphs were detected, indicating that the predicted breeding following December rainfall was not significant in the southern Central West.
  • There was localised light–moderate rainfall (<20-40 mm) in the Nyngan area during the first week of January, light rainfall (<20 mm) in the Central Tablelands and eastern Central West LLS areas during 8­–15 January and moderate–heavy rainfall (20–>40 mm) in parts of the Northwest LLS area during the last week of January. Pasture vegetation is becoming dry in most areas.

Forecast

  • Habitat conditions deteriorated in most areas during January, which resulted in limited breeding opportunities. However, localised storm rainfall occurred in parts of the Central West in early January and the widespread rain in Northwest LLS area at the end of the month could have initiated low density egg laying. It is likely that some nymphs will develop during February, with several different hatching times possible, but given the low adult population level, most nymphs will be at low densities.
  • The probability of a large population increase in autumn has declined as no significant summer breeding occurred.
  • There is a low probability of significant immigration from other regions during February or autumn.

Risks

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

Riverina
Riverina and Murray Local Land Services

Locusts and conditions

  • The regional locust population level remained low during January. There were no reports
  • Survey in mid-January identified only Isolated density adults in the Hay, Deniliquin, Griffith and Lake Cargelligo districts. No nymphs were detected, indicating that any breeding following December rainfall was not significant.
  • There was light rainfall (<20 mm) in the eastern Riverina LLS during the first week of January and further localised, light–moderate falls (<20–40 mm) during the last week of January. Pasture vegetation is becoming dry in many areas.

Forecast

  • Locust population level is likely to remain generally low during February and autumn. Rainfall in eastern districts at the end of January will produce some pasture growth, which could initiate sporadic low density breeding. Low density nymphs could develop in those areas after mid-February, but these would likely to contribute to a small increase in adult numbers in March.
  • Some earlier undetected breeding was possible following the widespread rainfall in December, and fledging the resulting nymphs from late January could contribute to local increases in adult numbers to Scattered density during February.
  • There is a low probability of significant immigration from other regions during February or autumn.

Risks

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

Far West and Far Southwest
Western Local Land Services

Locusts and conditions

  • Locust population levels remained low in surveyed areas during January.
  • The Far Southwest region was surveyed in mid-January. Only occasional Isolated density adults were identified in the Broken Hill, Menindee, Wentworth and Balranald districts. Residual Scattered density adults were recorded in the Ivanhoe district. No nymphs were detected, indicating the predicted population increase in the Southwest during February is now unlikely.
  • Limited survey of the Far West region identified only Isolated density adults in the Wilcannia and White Cliffs districts.
  • The Fowlers Gap and White Cliffs light traps recorded no locusts during January.
  • There was localised light rainfall (<20 mm) in the Ivanhoe and Wanaaring districts during mid-January. There was localised light–moderate (20-40 mm) storm rainfall in the Bourke district during the last week of January. Pasture vegetation is now dry in most areas.

Forecast

  • Habitat conditions deteriorated in most areas during January, which limited breeding opportunities and may have increased the mortality of any nymphs. However rainfall has been dominated by isolated storms and some localised heavy falls could have initiated sporadic egg laying. Low density nymphs could develop in some areas during February, but are only likely to contribute to a small increase in adult numbers in March.
  • The likelihood of a large population increase during autumn has declined as a result of continued low adult numbers and limited breeding opportunities.
  • There is a low probability of any significant immigration from other regions during February or autumn.

Risks

  • There is a low risk of widespread regional infestations developing during February 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 is expected to have remained very low during January.
  • No survey was conducted and there were no reports of locust activity. Sequences of high temperature (>40° C) days during January are likely to have resulted in increased mortality rates of adults and any nymphs.
  • The Birdsville and Nooyeah Downs light traps did not record any locusts during January.
  • There was localised light rainfall (<20 mm) in parts of Diamantina Shire during 7–14 January. Pasture vegetation is dry in most areas.

Forecast

  • Habitat conditions remain unfavourable for locust breeding. Given the very low population densities previously recorded, any eggs laid during February are likely to produce only low density nymphs and the dry vegetation and extreme temperatures are likely to increase nymph and adult mortality rates.
  • There is a low probability of a significant population increase in February or autumn.
  • There is a low probability of immigration from other regions during February or autumn.

Risks

  • There is a low risk of a widespread infestation developing during 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 January. There were no reports.
  • Survey of the Longreach and Barcaldine Regional Council (RC) areas in mid-January identified only Isolated density adults. No nymphs were detected.
  • The Longreach light trap recorded no locusts during January.
  • There was light–moderate localised storm rainfall (<20-40 mm) in the Barcaldine RC area during the first week of January. Pasture vegetation remains dry in most areas.

Forecast

  • Locust population levels are expected to remain low in these regions during February and autumn. Dry habitat conditions in the Northwest region and much of the Central West will limit breeding opportunities.
  • The likelihood of further breeding and an early autumn nymph generation will depend on the extent of rainfall in 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 February or autumn.

Central Highlands
Central Highlands and Isaac Regional Council

Locusts and conditions

  • Locust population densities remained generally low during January. There were no reports.
  • Survey in late January identified Isolated–Scattered density adults in many habitat areas of Central Highlands RC and Banana Shire, with occasional adults in parts of Isaac RC area. Present density third–fifth instar nymphs were recorded in the Rolleston, Taroom and Mitchell districts, indicating some breeding occurred during December.
  • Several other species were also recorded, including low numbers of migratory and spur-throated locusts, and Numerous density Oedaleus australis, the eastern Oedaleus.
  • There was moderate–heavy storm rainfall (20->40 mm) throughout the region during the first week of January. However, pasture grasses are becoming dry in many areas.

Forecast

  • Remaining nymphs will fledge in early February and could contribute to localised increases in adult numbers, up to Numerous density. Rainfall in early January maintained favourable habitat conditions in some areas, but vegetation was becoming dry by the end of the month. The likelihood of further breeding and an autumn nymph generation will be influenced by the distribution of rainfall in February.
  • There is a low probability of immigration from other regions during February or autumn.

Risks

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

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

Locusts and conditions

  • The locust population level remained generally low in surveyed areas during January.
  • Survey of the Roma–Mitchell area in late January identified Isolated–Scattered density adults and occasional late instar nymphs.
  • There was light–moderate storm rainfall (<20-40 mm) in parts of Western Downs RC area during the first week of January. Pasture vegetation is drying out in most areas.

Forecast

  • Locust population levels are likely to remain generally low during February and autumn. Fledging of remaining nymphs is likely only to maintain the current adult population level. However, breeding in December may have been more be more widespread throughout the region and localised increases in adult numbers to Numerous density are possible. The likelihood of further breeding and an autumn nymph generation will be influenced by the distribution of rainfall in February.
  • There is a low probability of significant immigration from other regions during February of autumn.

Risks

  • There is a low risk of a widespread regional infestation developing during February 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 January as habitat conditions remain very dry in most regions.
  • No survey was conducted and there were no reports of locust activity.
  • The Dulkaninna and Oodnadatta light traps recorded no locusts during January.
  • There was light–moderate rainfall (<20–40 mm) in western parts of the Northwest region during the first two weeks of January. Pastures are dry in other areas.

Forecast

  • Locust numbers are likely to remain low in these regions during February and autumn. The very low population level identified over recent months and dry habitats indicate that no significant breeding is likely.
  • There is a low probability of significant migrations into these regions during February or autumn.

Risks

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

Murray Valley, Mt Lofty Ranges & Southeast Region

Locusts and conditions

  • Locust numbers are likely to have remained very low in these regions during January.
  • There was no significant rainfall (<20–40 mm) in these regions during January.

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 February 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 numbers are likely to have remained very low during January.
  • Reports in North Central and southern Victoria were of wingless grasshoppers, Phaulacridium vittatum.
  • Landholders near Swifts Creek in Gippsland reported that C. terminifera were still present in the area during January.
  • There was light–moderate rainfall (<20–40 mm) in North Central Victoria during the last week of January.

Forecast

  • Habitat conditions remain favourable for locust breeding in parts of North Central Victoria, but given the current low adult population level, any nymphs developing during February are only likely to maintain the background population level.
  • There is a low probability of any significant immigration during February of autumn.

Risks

  • There is a low risk of a widespread infestation developing during February 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