Locust Bulletin November 2016

​​​​​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 forecast an​d maps of locust distributions.​

General situation in October and outlook to January 2017

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Australian plague locust - Chortoicetes terminifera

Two separate cohorts of nymphs developed during October. Autumn locust breeding resulted in high density nymphs developing in small areas of Far Southwest New South Wales and the Flinders Ranges area of South Australia. Breeding by the earlier population in August in Southwest and part of Northwest Queensland gave rise to a widespread low density nymph population in those regions and adjacent parts of northern South Australia in October. Fledging of those nymphs in late October produced medium density adults in Southwest Queensland and localised higher density adults and small swarms in the Arrabury area. Adult numbers were generally low in other regions, and low density spring generation nymphs were recorded in Far West New South Wales, Bulloo Shire and the Central West, South Central and Central Highlands regions of Queensland.

In New South Wales, October surveys identified consistent low density adults in the Far West and Far Southwest regions, but localised high density nymphs and medium density fledgling adults developed in a small area south of Broken Hill. Only occasional low density adults were recorded in the Central West and Northwest regions.

In western Queensland, widespread low density nymphs developed in the Diamantina, Barcoo and Winton Shires. Medium density adults were recorded in the Birdsville–Betoota area and small fledgling swarms, associated with residual nymphs, in the Arrabury area. Low density adults were consistently recorded in all shires of the Southwest region. Only occasional low density adults and nymphs were recorded in the Central West, South Central and Central Highlands regions.

In South Australia, medium density adults were recorded in the Hawker–Parachilna area on the western side of the Flinders Ranges, and high density fledgling adults and late instar nymphs were identified in the Parachilna–Commodore area. Medium density adults, associated with low density late instar nymphs were also recorded in the Innamincka–Cordillo Downs area in the Far North region in October. Only occasional adults were recorded in other areas of the Far North and Northeast regions. Primary Industries and Regions South Australia (PIRSA) also received several reports of nymphs in the Flinders Ranges and from several locations in the Western Agricultural region.

No reports have been received from Victoria, but the autumn distribution of adult locusts in the North Central and Northwest regions suggests that nymphs are likely to have hatched in some areas during October. Some localised low and medium density nymphs are expected to develop during November and would fledge at the end of the month.

The outlook for the remainder of 2016 is for a moderate increase in adult population levels to widespread medium densities in Far West and Far Southwest New South Wales, Southwest and part of Northwest Queensland, and parts of the Far North, Western Agricultural and Northeast regions of South Australia. Localised high densities are possible where high density nymphs developed, but no significant swarm formation is likely. A general population increase from very low densities recorded in other regions is also likely. However, habitat conditions remain favourable for localised breeding in several regions during November, which could produce a nymph generation during December. As vegetation continues to dry out, the extent of any summer nymph infestations will be influenced by the distribution of rainfall. There is a low risk of widespread high density infestations in any region before 2017.​

3 November 2016

Spur-throated locust - Austracris guttulosa

There is a widespread medium density adult population throughout the Central West, Northwest, Southwest, Central Highlands and Queensland Gulf regions. Consistent high densities were recorded in northern shires of Northwest and Central West Queensland during September and October. There were several reports of swarms from the Winton–Cloncurry area in Northwest Queensland in recent months. Adults of this species usually commence breeding after the onset of the wet season. The unseasonal winter and September rainfall in Queensland and green habitat conditions throughout inland regions could have initiated early breeding in some locations.

Surveys in recent months identified consistent Scattered–Numerous density adults in Boulia and Winton Shire, and in Longreach, Blackall-Tambo, Barcaldine and Isaac Regional Council (RC) areas. Concentration density adults and several swarms were recorded in McKinlay, Cloncurry and Richmond Shires. Adults were recorded at Isolated–Scattered densities in the Southwest and South Central regions, and in Central Highlands RC area. Isolated density adults were identified in the Far North and Northeast regions of South Australia and in Far West New South Wales, with Scattered density adults recorded around Bourke.

Habitat conditions were favourable for early breeding in Queensland during September and October, but have become relatively dry in most areas north of 23°S. Sporadic egg laying might have commenced in October and some nymphs could appear during November. Egg development to hatching in this species takes 3–4 weeks and nymph development a further 8–10 weeks. Females can lay multiple times during summer. Nymphs of this species usually do not aggregate to form bands, but can reach densities of 30 m2 in favourable habitats. The survival of early stage nymphs can be limited in dry conditions.

The outlook is for an increase in population during 2016–17 as a result of the large potential breeding population and possible early commencement of egg development. The likelihood of an overall population increase will depend on the consistency of rainfall during the northern wet-season. There is a moderate risk of swarms persisting in the Central West and Northwest regions of Queensland during November and December.

Migratory locust - Locusta migratoria

Only occasional low density adults were identified in the southern Central Highlands region of Queensland in early October. Surveys identified Isolated density adults in the Buckland Plains area, Southwest of Springsure and in the Injune area. Isolated density adults were also recorded at one location near Alpha and near Longreach. Populations are persistent and rapid increases can occur in the Central Highlands and eastern parts of Central West Queensland. These regions received above average winter and September rainfall, which produced favourable habitat conditions for continued low density breeding, but pastures have dried out in the Isaac Regional Council area. However, variable and contracting green habitats can contribute to local gregarisation of this species.

There is a low probability of widespread gregarious populations developing in the Central Highlands, eastern Central West or South Central regions of Queensland during November or December. However, small gregarious populations could develop in localised areas of the Central Highlands during summer.

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 October to 31 October 2016

Map of Australian plague locust distribution 1 August to 30 September 2016 

Situation in October and forecast to January 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 remained at generally low densities and there were no reports.
  • Limited surveys were conducted in the Warren–Quambone–Carinda area of Central West LLS and the Walgett–Goodooga district of Northwest LLS in late October. Only occasional Isolated density adults were recorded and no nymphs were detected.
  • There was light–moderate rainfall (<20-40 mm) in these regions during 8–15 October. There were further light rains in the Moree district during the last week of the month. Pasture vegetation remains green in many areas.

Forecast

  • Initial surveys indicate no significant spring nymph generation, but low–medium density nymphs are likely to have developed in other areas, including the Condobolin and Nyngan districts. Dense, wet ground vegetation may have increased nymph mortality in some areas. Fledging of surviving nymphs will occur during November, resulting in a moderate increase in adult numbers to Numerous density in localised areas.
  • Given the very low current population level, any breeding during November is only likely to result in moderate population increases in December and swarms are unlikely to result in summer.
  • There is a moderate probability of some low density immigration from the Far Southwest NSW region during November.

Risks

  • There is a low risk of widespread infestations developing during November or December.

Riverina
Riverina and Murray Local Land Services

Locusts and conditions

  • Locust population level is likely to have remained low during October. No APLC surveys were conducted and there have been no reports. APLC Survey are planned for November.
  • There is likely to have been some autumn egg laying and the majority of eggs will have entered diapause. Hatching will have commenced in late September in northern districts and mid-October in the south. Dense, wet pasture vegetation could have reduced nymph survival of early instar nymphs in some areas.
  • There was light–moderate rainfall (<20–40 mm) across the region during the first week of October, and further light rains in the eastern districts during 15–21 October. Pasture vegetation remained green, but ephemeral grasses will dry off in November.

Forecast

  • Nymphs are likely to develop at low–medium densities, with localised high densities possible in some areas, including the Hillston and Deniliquin districts. Fledging of surviving nymphs will occur from mid-November, but a large adult population increase, or any swarm formation, is unlikely.
  • Breeding of spring generation adults is not likely before December.
  • There is a low probability of significant immigration from other regions during.

Risks

  • There is a low risk of a widespread regional infestation developing during November or December.

Far West and Far Southwest
Western Local Land Services

Locusts and conditions

  • There is a widespread low density adult population throughout the region. Localised high density nymphs and adults developed in one area south of Broken Hill.
  • Surveys were conducted in districts of the Far West region in mid-October. Isolated–Scattered density adults were consistently identified in the Broken Hill, White Cliffs, Wilcannia, Tibooburra, Wanaaring and Bourke districts. Numerous density mid-instar nymphs were detected at one location in the Cobham Lake area and Present density nymphs in the Wanaaring area.
  • Surveys south of Broken Hill in mid-October identified localised Numerous density adults and several small areas of Sub-band density mid-instar nymphs in the Netley area. Sampled female adults showed some development. Isolated density adults were recorded in the Wentworth and Ivanhoe districts of the Far Southwest region.
  • Surveys of the Broken Hill district at the end of October identified further localised Numerous–Subband nymphs in the Netley area. Nymphs were final instar stage and were associated with Numerous density fledgling adults. There were Isolated–Scattered density adults in the Menindee and Willandra Lakes areas, and Scattered–Numerous density adults south of Wilcannia.
  • The Fowlers Gap and White Cliffs light traps recorded low numbers of locusts on several nights in mid-October.
  • There was light rainfall (<20 mm) in the western half of the Far West and throughout the Far Southwest region during the first week of October, with moderate falls (20-40 mm) in the Wilcannia–Ivanhoe district. Pasture vegetation was drying off in many areas in late October.

Forecast

  • Nymphs were likely to be more widespread in the Far Southwest region than detections indicate. The high density nymphs identified south of Broken Hill represent a localised infestation, but Scattered–Numerous density adults near Wilcannia may also have been recently fledged.
  • Fledging of spring nymphs commenced in mid-October in the Far West region and will continue in early November in the Far Southwest. Adults are likely to disperse from the Netley area and numbers are likely increase to overall Numerous density in parts of the Far Southwest. Any swarm formation is likely to be restricted to small areas.
  • Sporadic medium–high density egg laying is possible during November, particularly in the Broken Hill, Wilcannia, Ivanhoe and Balranald districts, where vegetation and soil conditions remain locally favourable after very heavy rainfall during September. Conditions are becoming dry in much of the Far West region, but sporadic egg laying is possible in some areas. Assuming mostly immature adults in late October, egg laying would commence in mid-November and hatching at the start of December. Possible earlier laying could produce nymphs in late November. The probability of widespread breeding will decline during December in the absence of moderate–heavy rainfall.
  • There is a moderate probability of redistribution within the region or small migrations to adjacent regions of New South Wales, South Australia or Victoria during November.

Risks

  • There is a low risk of a widespread regional infestations developing during November or December.

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 current distribution of young adults and nymphs indicates breeding in late August and early September. There were widespread low density nymphs in the region during October, with localised high density adults in southern Barcoo Shire.
  • Quilpie and Bulloo Shires were surveyed in mid-October. Isolated–Scattered density adults were identified in most areas, along with Present density late instar nymphs in the Nockatunga and Naryilco areas.
  • Surveys of Diamantina and Barcoo Shires in late October identified Scattered–Numerous density adults throughout the Birdsville–Betoota–Arrabury area. Several small areas of Concentration and swarm density fledgling adults, associated with mid–late instar nymphs were recorded near Arrabury. Present density mid- and late instar nymphs were also recorded in the Bedourie–Coorabulka and Monkira–Mooraberrie areas. Most of these nymphs are the result of localised breeding in early September. Isolated–Scattered density adults were recorded elsewhere in these shires.
  • The Birdsville light trap recorded low numbers of locusts on 27 October.
  • There was localised light–moderate rainfall (<20–40 mm) in southern Barcoo and Bulloo Shires during the first week of October. Habitats remain green in many areas in late October, but will dry out during November.

Forecast

  • Fledging of remaining nymphs in early November will contribute to an increase in overall adult numbers to Numerous density in many areas, although any further swarm formation is likely to be restricted to small areas. Adults are likely to disperse to favourable habitat areas and egg laying is possible from mid-November. This could result in a further localised nymphs developing in December.
  • In the absence of heavy rainfall during November or December, habitat conditions will become unsuitable for widespread locust breeding. The population level will gradually decline in dry conditions during summer. However, single storm rainfall events could initiate localised breeding that would produce a summer nymph generation.
  • There is a moderate probability of adult redistribution within the region during November and of small migrations to adjacent regions, but this will decline in December.

Risks

  • There is low risk of a widespread regional infestation developing during November or December.

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 was generally low in areas surveyed during October.
  • Parts of Longreach, Blackall-Tambo and Barcaldine Regional Council (RC) areas were surveyed in mid-October. Only Isolated density adults were identified in most areas, but Isolated–Scattered density adults and Present density late instar nymphs were recorded in the Tambo district.
  • Surveys in Winton and Boulia Shires in late October identified Isolated–Scattered density adults and Present density late instar nymphs. There were Present density third–fifth instar nymphs at several locations to the west of Winton. Nymph ages indicate egg laying occurred in early September.
  • The Longreach light trap recorded no locusts during October.
  • There was localised light–moderate rainfall (<20-40 mm) in southern Longreach and Blackall-Tambo RC areas during the first week of October, and further light–moderate falls in the Tambo area in the last week of the month. Pasture vegetation remained green in areas south of a line from Winton to Aramac, in mid-October, but will becoming dry during November.

Forecast

  • Locust population levels are expected to remain generally low in these regions during November and December, but adult numbers could increase to Numerous density in some areas as spring generation nymphs fledge. Drying vegetation will limit breeding opportunities in most of the region, but habitats remain favourable in southern Longreach and Blackall-Tambo RC areas. Sporadic egg laying by the current low density adult population could produce localised nymphs in late November or December.
  • There is a low probability of significant immigration during November and December.

Risks

  • There is a low risk of a widespread regional infestations developing during November or December.

Central Highlands
Central Highlands and Isaac Regional Council

Locusts and conditions

  • Locust densities remained generally low during October.
  • Surveys in mid-October identified Isolated density adults in the Twin Hills area, north of Clermont, and the Emerald–Rolleston area. Present density mid-instar nymphs were recorded near Springsure and Rolleston.
  • There was localised light rainfall (<20 mm) in western parts of the region during 20–25 October.

Forecast

  • Fledging of spring nymphs is likely to maintain the overall low adult densities. Habitat conditions remain suitable for further localised locust breeding in Central Highlands RC area, which could produce low density nymphs in late November or December.
  • There is a low probability of immigration from other regions during November or December.

Risks

  • There is a low risk of a widespread infestation developing during November or December.

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

Locusts and conditions

  • Locust population levels remained generally low in surveyed areas during October.
  • Surveys of the Maranoa Regional Council (RC) and Murweh Shire in mid-October identified Isolated density adults and occasional Present density mid-instar in the Roma–Jackson and Mitchell–Moorak areas.
  • There was light–moderate rainfall (<20-40 mm) in Paroo and Balonne Shires and the Goondiwindi RC area during the first week of October. Pasture vegetation is becoming dry in many areas.

Forecast

  • Fledging of nymphs in early November is likely to produce local increases in adult numbers. Given the current low population levels, this could result in Numerous density adults in some areas.
  • Nymphs are likely to have developed in other parts of the region and Scattered–Numerous density adult numbers could be more widespread in other districts as a result during November.
  • There is a low probability of significant immigration from other regions during November or December.

Risks

  • There is a low risk of a widespread regional infestation developing during November or December.

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

  • Localised nymphs developed from autumn breeding in the Parachilna area of the Far North region and parts of the Western Agricultural region. Breeding by the late winter generation near the Queensland border in the Far North region produced localised nymphs in October.
  • Surveys of the Innamincka area in mid-October and the Cordillo Downs–Cadelga and area in late October identified Scattered-Numerous density adults and Present–Numerous density mid–late instar nymphs. These locusts are part of a wider population in Southwest Queensland. High density late instar nymphs were recorded in that area in favourable habitats in early August and the development stages of the present population indicates egg laying in early September.
  • Following reports from the Parachilna area, surveys in late October identified Numerous density fledgling adults and Numerous density residual late instar nymphs. There were Scattered–Numerous density adults in the Hawker area and Isolated-Scattered densities south to Wilmington, Orroroo and Peterborough. Only occasional Isolated density adults were recorded on the eastern side of the Flinders Ranges and in the Burra–Sturt Vale and Yunta areas.
  • PIRSA received a reports of dense nymphs in the Flinders Ranges between Balcanoona and Hawker, and from near Buckleboo and Ceduna, in the northern Eyre Peninsula district during October.
  • The Dulkaninna light trap did not record any locusts in October.
  • There was light rainfall (<20 mm) in parts of the western Agricultural region in mid-October. Pasture vegetation is green.

Forecast

  • Localised, low and medium density nymphs are likely to have developed in other parts of the Western Agricultural, Murray Valley and Northeast regions during October and an increase in adult numbers to Numerous density is likely in some areas in November.
  • Breeding and sporadic egg laying is possible in residual green habitats of the Far North or Northeast region during November. Localised nymphs could develop at low–medium densities in late November or December.
  • There is a moderate probability of small immigrations from Southwest Queensland or from the Broken Hill district into adjacent areas of the Far North or Northeast regions during November.

Risks

  • There is a low risk of widespread regional infestations developing November or December.

Murray Valley, Mt Lofty Ranges & Southeast Region

Locusts and conditions

  • Locust densities are expected to have remained low. No surveys were conducted and there have been no reports.
  • There was light–moderate rainfall (<20-40 mm) in these regions during mid-October. Vegetation remains green in many areas, but ephemeral grasses will dry off during November.

Forecast

  • Fledging of any local spring nymphs will occur in November, but is only likely to maintain a low regional adult population level.
  • There is low probability of any significant immigration during November or December.

Risks

  • There is a low risk of a widespread infestation developing during November or December.

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 low during October. No APLC surveys were conducted.
  • Spring hatchings would have commenced in early October in the Northwest region and mid-October in North Central Victoria and the Wimmera.
  • There was moderate rainfall in Northwest and North Central Victoria during the first week of October and further light–moderate rainfall (<20-40 mm) in mid-October. Pasture vegetation remains green in most areas as a result of heavy rainfall during September, but ephemeral grasses will dry off during November.

Forecast

  • There were several reports of low and medium density locusts in the North Central and Northwest regions, and as far south as the Wimmera district in autumn. Low and medium density nymphs are likely to develop in localised areas during November, but any high densities or Bands are likely will be restricted to small areas in the North Central region.
  • Dense, wet ground vegetation may increase nymph mortality in some areas. Fledging of surviving nymphs will occur after mid-November, and a moderate increase in adult numbers is likely.
  • Any breeding of spring generation adults is not likely before December.
  • There is a low probability of significant migrations from Far Southwest New South Wales during November.

Risks

  • There is a low risk of a widespread infestation developing during November or December.

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.

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

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