Locust Bulletin March 2017

​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.

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General situation in February and outlook for Autumn 2017

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Australian plague locust - Chortoicetes terminifera

Locust populations declined to low densities in most regions during February. However, breeding in December in the Oodnadatta–Coober Pedy area of Northwest South Australia produced a nymph generation that fledged at the end of January. Widespread medium density adults were recorded in early February and transient swarms formed in the Oodnadatta area. Breeding also occurred in the Far North and Northeast regions, where young adults and late instar nymphs were identified in several areas.

The locust population level declined to low densities in New South Wales during February. Only occasional low density adults were identified in Central West and Northwest Plains regions, with more consistent counts in the Broken Hill–Tibooburra and Bourke areas of the Far West region. No nymphs were detected during surveys and habitat conditions are now generally dry in most regions.

In Queensland, consistent low density adults and occasional late instar nymphs were recorded in the Central West, South Central, Northwest and Southwest regions during February. Medium density adults were identified in the Birdsville area of Diamantina Shire.

In South Australia, a widespread population of medium density adults and mostly mid-instar nymphs was identified in the Oodnadatta–Mt Barry–Coober Pedy–Marla area in early February.  A number of swarms were recorded in the Oodnadatta area, containing both immature and gravid females. Adult densities were low in most of the Far North region, but localised bands of late instar nymphs and medium density adults were recorded near Dulkaninna and Murnpeowie. More widespread low and medium density late instar nymphs were recorded from Hawker to Peterborough in the Northeast region. High density nymphs were also reported from the Ceduna area of the Western Agricultural region in mid-February.

Population levels remained generally low in Victoria. However, noticeable numbers of adults were reported in the Echuca–Mitiamo area in early February and persisted in northern Victoria throughout the month.

The autumn outlook is for locust population densities to remain generally low in most regions of New South Wales and Queensland. A decline in adult numbers is likely in the Far North, Northeast and Northwest regions of South Australia during March. However, there is the potential for a nymph generation to develop in localised areas of northern South Australia and possibly in Southwest Queensland during March if swarms laid in habitats made favourable by the heavy rainfall at the end of January. Adult numbers will increase in the Western Agricultural region of South Australia during March, with the possibility of localised swarm activity and sporadic egg laying. There is a moderate probability of low density migrations within South Australia during March and April, with the likelihood of some southward movements. Medium density populations could establish in southern South Australia and New South Wales, and northern Victoria during autumn. The majority of eggs laid in these regions in March or April will be at low densities and will remain in diapause dormancy during winter.  There is a low probability of swarm infestations in any state during autumn. Consequently, there is a low risk of widespread nymph infestations developing in agricultural regions during spring.

3 March 2017

Spur-throated locust - Austracris guttulosa

There was a widespread medium density population throughout inland Queensland during February, with a relative decline in breeding adult numbers detected in some regions. There were also widespread, low and medium density nymphs in Central West and Northwest Queensland, and similar populations are likely in to be the Queensland Gulf and Central Highlands regions. Low density nymphs were recorded in the Southwest and South Central regions.

Surveys in February identified Scattered–Numerous density adults in Central West and Northwest Queensland, along with Present–Numerous density nymphs, mostly at middle and late instar stages, at many locations. Present density nymphs and Isolated–Scattered density adults were recorded in Diamantina and Quilpie Shires in the Southwest and Murweh Shire in South Central Queensland. Occasional adults were recorded in the Far West and Northwest Plains regions of NSW.

Heavy rainfall was restricted to parts of the Central West, South Central, Central Highlands and Gulf regions of Queensland during February. This will enable nymphs currently in those areas to survive to fledging and some breeding to continue. Females can lay several pods over the course of the wet season. Egg development to hatching in this species takes 3–4 weeks and nymph development a further 8–10 weeks. Further nymphs are likely to develop during March, but hatchings should decline in April. Fledging of nymphs hatched in previous months will continue and the numbers of young adults will increase during autumn. These will largely replace the previous generation as it ages and declines, although some swarms are likely to form in late autumn. There is a low risk of a large increase in overall population level during 2016–17.

Migratory locust - Locusta migratoria

The Queensland Central Highlands region was not surveyed during February and this species was not detected in other regions. However, previous surveys identified low numbers of adults in the southern Central Highlands.

Rapid population increases can occur in the Central Highlands, eastern Central West and South Central regions of Queensland. Rainfall during February will produce favourable habitat conditions for continued localised breeding during autumn. Small gregarious populations could develop in localised areas of the Central Highlands, but there is a low probability of a widespread infestation developing during autumn or winter.

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.

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Australian plague locust distribution 1 February to 28 February 2017

Map of Australian plague locust distribution 1 January to 3 February 2017

Australian plague locust (Chortoicetes terminifera)

Situation in February and forecast for Autumn 2017

New South Wales

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

Locusts and conditions

  • The locust population declined to low densities during February. There were no reports of locust activity.
  • Surveys in the Central West Local Land Services (LLS) area in mid-February identified Isolated–Scattered density adults in the Dubbo, Nyngan and Coonamble districts. Isolated–Scattered density adults were also recorded in the Narrabri and Moree districts of the Northwest LLS. No nymphs were detected during surveys.
  • There was patchy light rainfall (<20 mm) in eastern parts of the Central West LLS during the first week of February. There was light–moderate rainfall (<20-40 mm) in the Narrabri and Moree districts of Northwest LLS during 15–21 February. Pasture vegetation is dry in most areas of these regions.

Forecast

  • No significant breeding is likely to have occurred during February, as habitat conditions were dry in most areas. Low density egg laying was possible in eastern districts, but given the low population level this is only likely to result in maintaining background population levels during autumn.
  • Any autumn breeding is likely to be at low densities. The majority of eggs laid during autumn will enter diapause dormancy and not hatch until spring.
  • The adult population is likely to remain at low densities during autumn.
  • There is a low probability of significant immigration from other regions during autumn.

Risks

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

Riverina
Riverina and Murray Local Land Services

Locusts and conditions

  • The locust population is expected to have remained at a low level during February, given the dry habitat conditions in most areas. No surveys were conducted.
  • Low density adults were reported from the Mathoura and Kyalite areas in Murray Local Land Services (LLS) area in the first half of February. These were possibly immigrants from Far West or Far Southwest regions.
  • There was patchy light rainfall (<20 mm) in the eastern areas of Riverina LLS during the first week of February, and further isolated storms during 8–14 February. Pasture vegetation is dry in most areas.

Forecast

  • No significant breeding is likely during autumn, given the dry habitat conditions in most areas and the low level background population.
  • The majority of any eggs laid during autumn will enter diapause and remain dormant during winter.
  • There is a moderate probability of low density exchange migrations with adjacent regions, but large immigrations are unlikely.

Risks

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

Far West and Far Southwest
Western Local Land Services

Locusts and conditions

  • Locust population level declined to low densities in surveyed areas during February. Habitat conditions became unfavourable for breeding in most areas. Sustained high daytime temperatures may have increased mortality in all life stages in January and February.
  • Surveys of the Far West region in mid-February identified Isolated–Scattered density adults in the Broken Hill–Milparinka–Tibooburra and Bourke–Louth–Tilpa areas. No nymphs were detected.
  • The Far Southwest region was not surveyed during February.
  • The Fowlers Gap and White Cliffs light traps recorded only very low numbers of locusts during the second half of February.
  • There was no significant rainfall in these regions during February. Pasture vegetation is becoming dry in most habitat areas.

Forecast

  • There is unlikely to have been any significant breeding during February, as most habitats have become dry. Only occasional nymphs are likely to develop during March and are only likely to maintain the low regional population levels.
  • The majority of any eggs laid from late March in the Far West region, and from mid-March in the Far Southwest, will enter diapause and not hatch until early spring.
  • There is a moderate probability of small exchange migrations between adjacent regions, and some immigration from northern South Australia is possible during autumn.

Risks

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

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

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Southwest
Barcoo, Bulloo, Quilpie and Diamantina Shire

Locusts and conditions

  • The adult population remained at generally low densities in surveyed areas during February, after declining in January. Extreme daytime temperatures may have caused increased mortality in all life stages.
  • Surveys of Quilpie Shire at the start of February identified Isolated–Scattered density adults and occasional mid-instar nymphs.
  • Surveys of Diamantina Shire in mid-February identified Scattered–Numerous density adults in most areas, with Numerous density recorded in the Birdsville area. Present density late instar nymphs were detected at several locations.
  • No locust were recorded at the Birdsville light trap during February. The Nooyeah Downs light trap recorded low numbers of locusts during the last week of February.
  • There was no significant rainfall in this region during February. Vegetation is becoming dry in most locust habitat areas.

Forecast

  • Habitat conditions became unfavourable for locust breeding in much of the region during February. However, heavy rainfall in late January in Diamantina Shire could have initiated some egg laying in early February, with the potential for nymphs to have developed in the second half of the month. Fledging of nymphs during March could maintain adult numbers at Numerous density in parts of the region. Adult numbers should decline to low levels in late autumn.
  • There is a moderate probability of some low density exchange migration with adjacent regions during March and April.

Risks

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

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 remained at generally low levels in surveyed areas during February.
  • Surveys in the Central West in mid-February identified consistent Scattered density adults in Longreach Regional Council (RC) area, and occasional adults in the Blackall-Tambo RC area. Present density mid-instar nymphs were detected at one location near Blackall. In the Northwest region, Isolated–Scattered density adults were recorded in many areas of Winton, Cloncurry and Boulia Shires.
  • The Longreach light trap recorded low numbers of locusts on several mornings in mid-February, with a peak of 62 on 20 February.
  • There was localised heavy rainfall in Richmond Shire during 8–14 February, and in Barcaldine Regional Council (RC) area during 15–21 February. There was moderate–heavy storm rainfall (20->40 mm) in parts of the northern shires of the Central West and Northwest regions during February. There was light rainfall in parts of Boulia and Winton Shires during the last week of February.

Forecast

  • Locust population levels are expected to remain generally low in these regions during autumn.  Any breeding by the local population in February is likely to produce only localised, low density nymphs in March. Adult population levels are therefore unlikely to increase significantly.
  • There is a low probability of significant immigration during autumn.

Risks

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

Central Highlands
Central Highlands and Isaac Regional Council

Locusts and conditions

  • The locust population level is likely to have remained generally low during February, but breeding by previously recorded locusts in the southern Central Highlands RC area may have maintained a localised Numerous density population.
  • APLC did not survey this region during February and there were no reports of locust activity.
  • There was patchy light–moderate rainfall (<20-40 mm) in parts of the region during the second and final week of February. Some areas of the southern Central Highlands RC area and Banana Shire received totals >50 mm.

Forecast

  • Rainfall during February has provided localised favourable vegetation and soil conditions for locust breeding.  Fledging of any subsequent nymphs would likely only maintain the low regional population density, but there is the potential for local population increases in the Arcadia Valley and Springsure areas.
  • There is a low probability of immigration from other regions during autumn.

Risks

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

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

Locusts and conditions

  • Locust population levels remained low in surveyed areas during February.
  • Survey in part of Murweh Shire in early February identified Isolated–Scattered density adults and occasional mid-instar nymphs in areas west of Charleville.
  • Surveys of Goondiwindi, Western Downs and Maranoa RC areas, and Balonne Shire in mid-February recorded only Isolated density adults and no nymphs were detected.
  • There was light–moderate rainfall (<20-40 mm) in Murweh Shire and Maranoa RC area during 15–21 February and further localised light–moderate falls in other districts during the last week of the month.

Forecast

  • Any local breeding is likely to maintain the overall low regional population density.
  • There is a low probability of significant immigration from other regions during autumn.

Risks

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

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

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Far North, Northeast, Northwest & Western Agricultural Region

Locusts and conditions

  • Heavy rainfall during December and January, particularly in the Far North and Northwest regions, provided several opportunities for locust breeding and favourable habitat for nymph development. Nymphs developed in the Oodnadatta–Coober Pedy area of the Northwest region during January and swarms formed in localised areas in early February.
  • Surveys of the Northwest, Far North and Northeast regions in early February identified widespread Scattered–Numerous density adults and low density nymphs at middle and late instar stages in the Coober–Pedy–Oodnadatta–Marla area. Several swarms were recorded in the Allandale area, southeast of Oodnadatta, on 6 February after low numbers were recorded the previous day. Transient swarms had been reported from other locations in that area over previous weeks, indicating frequent redistribution and migrations in the region in early February. Females were immature in some swarm samples and gravid in others. Subsequent reports indicate adult activity had declined in the Oodnadatta area and Northwest region by late February.
  • Population densities were lower elsewhere in the Far North region, with Isolated-Scattered density adults in most areas, except near Dulkaninna and Murnpeowie where localised Numerous–Band density late instar nymphs and swarm density young adults were recorded. Extreme high temperatures during January and February may have caused increased mortality in all locust life stages. On the western side of the Flinders Ranges in the Northeast region, Present–Numerous density late instar nymphs, along with Numerous density adults, were recorded at many locations in the Hawker–Cradock area. Isolated density adults were recorded in other surveyed areas of the Northeast region.
  • Landholders reported locust nymphs and some Bands in the Ceduna–Penong area of the Western Agricultural region in mid-February. An adult population was reported to have been present in January and rainfall in the region produced favourable conditions for locust breeding.
  • The Dulkaninna light trap recorded low numbers of locusts in early February. The Oodnadatta light trap was not operational.
  • There was moderate–heavy rainfall (20->40 mm) in the Western Agricultural region during the first week of February. Vegetation remains green in some areas of locust habitat.

Forecast                                                                

  • Vegetation and soil conditions remained favourable for breeding in some habitat areas in the first half of February. Localised laying was likely and there is a potential for a further nymph generation during March. Nymphs are likely to develop at low–medium densities, but some Bands could develop in drainage line and low-lying habitats.
  • Nymphs in the Western Agricultural region will fledge in early March and could persist in areas of green habitat. However, any eggs laid in March and April will enter diapause and remain dormant during winter.
  • There is a moderate probability of some migrations within South Australia or to western New South Wales during March. There is moderate risk of some southward migrations during autumn.

Risks

  • There is a moderate risk of small southward migrations from the Far North, Northwest and Northeast regions to the Western Agricultural and Murray Valley regions during autumn.
  • There is a low risk of widespread regional infestations during autumn.

Murray Valley, Mt Lofty Ranges & Southeast Region

Locusts and conditions

  • Locust densities are expected to have remained generally low during February. No surveys were conducted.
  • Local increases in adult numbers were reported in the Adelaide district in early February. Wind trajectories at that time suggest migration was possible from the Flinders Ranges area of the Northeast region, where fledging nymphs and young adults were recorded.
  • There was widespread light–moderate rainfall (20-40 mm) in these regions during the first week of February. Pasture vegetation in now drying off in many areas.

Forecast

  • Any local breeding during February is only likely to have maintained the low regional population level.
  • Migrations from the Northeast region could have produced small increases in adult numbers during February, and further migrations are possible in March and April.
  • Sporadic low density breeding is possible during autumn, but eggs will enter diapause and hatch in spring.

Risks

There is a low risk of a widespread infestation developing during 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

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North West & North Central Victoria

Locusts and conditions

  • Locust population levels are expected to have remained generally low during February, although adult activity was reported in some northern districts.
  • Locusts were first reported in the Echuca–Mitiamo-Boort area in early February, and persisted in noticeable numbers throughout the month.
  • There was widespread light–moderate rainfall (<20-40 mm) in Northwest and North Central Victoria during the first week of February. Pasture vegetation remains dry in most locust habitat areas.

Forecast

  • Any breeding of the local population during January is unlikely to result in a significant population increase.
  • There is a moderate probability of small migrations from western New South Wales or South Australia during autumn.

Risks

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

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.

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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