Locust Bulletin March 2011

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 and rainfall events. 

Locust Bulletin March 2011 — table of contents

General locust situation
Australian plague locust situation
Australian plague locust map February 2011
Rainfall February 2011
Terms and Abbreviations used in the Bulletin
Map of forecast districts used in the Bulletin
Map of forecast regions used in the Bulletin

General situation in February and outlook to April 2011

Australian Plague Locust
Spur–throated Locust
Migratory Locust

High density populations were confined to the southern margins of the range of suitable breeding habitats of this species during February. Fledging of nymphal bands commenced in early February in the southern Riverina of New South Wales and in North Central Victoria, which produced localised high density adults and a number of swarms. Fledging continued into late February in the Wimmera and Grampians districts in western Victoria and the Barossa Valley and Mt Lofty Ranges and Murray Valley in South Australia, with increases in adult numbers at that time. Egg laying in the infested regions during March or April will produce mostly diapause eggs which will not hatch until spring. Adult population density remained low in most other regions, but there was evidence of localised breeding and immigration in some areas.

The outlook is for continued swarm activity and localised egg laying in parts of North Central and western Victoria and southern South Australia, which is unlikely to produce significant further hatchings this autumn. The majority of eggs laid in these regions during autumn will not hatch until October, and high density nymphs may develop in some locations during spring. Some localised swarm egg laying is also possible in the south-eastern Riverina from early March. There is unlikely to be any significant immigration into agricultural areas from regions to the north during autumn, as there are no known large populations in northern New South Wales, northern South Australia, or Southwest Queensland.

In New South Wales nymphal bands were reported in the southern Hume and Riverina Livestock Health and Pest Authority (LHPA) areas in early February. Fledging continued during the first half of February and a number of swarms developed in the Albury–Corowa and Wagga–Cootamundra areas at the end of the month. Some high density egg laying is possible during March, but the majority of eggs laid after mid-March will enter diapause. Surveys indicate a low–medium density population and only occasional nymphs in most other areas of the state.

In South Australia nymphal bands developed in the Murray Valley and southern Northeast regions, and in the Barossa Valley area during February. Fledging of nymphs produced some high density adults in the Burra–Morgan area in mid-February and fledging continued throughout February in the Barossa Valley, Murray Mallee and Lower Murray districts. Several swarms were reported in the Riverland, the Burra-Eudunda area and the Barossa Valley in late February.
 
In Victoria several swarms were reported near Yarrawonga, Bendigo and Kyabram in North Central Victoria after mid-February. Band activity continued in the Grampians and southern Wimmera districts in late February, and fledging will extend to mid-March. Swarms are likely to form in these areas in early March and adult activity and swarm movement could continue into April. Localised high density egg laying is likely in the southern Wimmera and Grampians districts and in North Central Victoria. The majority of eggs laid from mid-March to mid-April will enter diapause and not hatch until October.
 
Surveys in western Queensland detected a continuing low density population in most regions. Localised Medium density adults were identified in parts of the South Central region. There is a low probability of a significant population increase during autumn.  

•  Spur–throated locust           Austracris guttulosa
  

Fledging of nymphs from summer egg laying has produced a significant widespread population of young adults throughout western Queensland and northern New South Wales. Adults at Concentration and swarm densities have been recorded in parts of Central West, Southwest, Northwest and South Central Queensland, and the Northwest Plains, Far West and Central West New South Wales. There is a consistent background population at Scattered–Numerous density throughout these regions. Nymphs at various development stages at low–medium densities are also widespread throughout these regions. Low density nymphs and adults have been recorded in southern New South Wales, northern Victoria and in South Australia. The range of nymph stages indicates egg laying commenced in November and continued through to January. There have been several reports of nymphs damaging citrus and cotton crops in parts of New South Wales during January and February. Nymphs have been recorded in citrus orchards from as far south as Griffith and Dareton in New South Wales, from Mildura in northern Victoria and Loxton in South Australia. Widespread successful breeding in New South Wales has not been recorded since 1974.

The outlook is for the formation of many swarms in several regions of western Queensland and northern New South Wales during autumn. Repeated egg laying during the November–February period and high rates of nymphal survival will result in a further significant population increase during 2011. Immature adults often form dense swarms in late autumn, which can persist throughout winter in woodlands and tree lines along rivers. Immature adults can also undertake migratory movements during autumn, which could result in redistribution and increases in density in other regions. At high densities, this species can cause economic damage to agriculture over several months. Survival of adults during winter is known in northern New South Wales and Queensland, but the survival rate in southern New South Wales may be lower due to prolonged exposure to low temperatures.

APLC surveys during December–February identified a significant, consistently distributed population of this species in many regions of New South Wales and Queensland. In New South Wales this represents a significantly higher level of summer breeding than has been recorded in recent years and nymphs have not been recorded developing in southern New South Wales before this year. Concentration and swarm density adults were identified in parts of the Quilpie, Blackall-Tambo, Roma, Balonne and Paroo Shire and Regional Council areas in Queensland, and the Darling, Northwest, Central West, Lachlan and Western LHPA areas in New South Wales. In other areas in these states adults were at Scattered–Numerous density in many areas, with lower densities of adults in Far Southwest New South Wales, northern Victoria and northern South Australia.

A significant infestation of nymphs of this species was reported in the Carnarvon area in Western Australia during February and the population is likely to be more widespread in northern areas of the state.  Widespread low density nymphs were reported from the Alice Springs area in the Northern Territory.  

Map of spur-throated locust distribution: December 2010 - February 2011

 

• Migratory locust                Locusta migratoria

APLC survey in early February identified Scattered density adults in several locations in the Mungindi area of the New South Wales Northwest LHPA area and in the Roma–Injune area of South Central Queensland. Occasional Isolated density adults were detected in the Central Highlands and near Dalby. There remains potential for the development of localised gregarious populations of this species in South Central or the Central Highlands of Queensland as a result of the sequence of heavy rainfall events over recent months.    

4 March 2011

• Australian plague locust situation

  New South Wales
  Queensland
  Victoria
  South Australia

Map of Australian plague locust distribution: February 2011

 

NEW SOUTH WALES

Situation in February and forecast to April 2011

Central West

Lachlan, Central West & Central North LHPA

Locusts and conditions

•  Adult densities remained generally low in Central West LHPA area, but some low level breeding produced medium density young adults in the Gilgandra and Warren areas in early February. In Lachlan LHPA, fledging of nymphs in the Young area produced localised Numerous and Concentration density adults in late February.

• APLC surveys during February detected Isolated–Scattered density adults throughout the region. Localised Numerous density young adults and Present density late instar nymphs were identified in the Gilgandra–Armatree area and north of Nyngan in early February. There were occasional Present density mid-instar nymphs in the Narromine–Warren area.

• Isolated–Scattered density adults were identified in the Gunnedah area of Central North LHPA in early February.

• Nymphs in the Young–Wallendbeen area fledged during February and overall adult numbers increased to Numerous density. Some localised Concentrations developed in mid-February and low density migratory movement to the east was reported at the end of the month.

• There was a widespread Scattered–Numerous density population of several species of grasshoppers, including Oedaleus australis, and spur-throated locusts throughout Central West LHPA.

• There was moderate–heavy rainfall (20–>40 mm) in southern Lachlan LHPA during the first week of February. There were widespread light rainfall (<20 mm)during 8–14 February, and further moderate falls (20–40 mm)throughout the region during 15–21 February. Pasture vegetation remains green in most areas.            

Forecast

• Some localised medium density egg-laying is possible during March, particularly in the southeast of Lachlan LHPA and the Gilgandra–Coonamble area of Central West LHPA. The majority of any eggs laid from mid-March will enter diapause and not hatch until spring. Any eggs laid earlier in Central West LHPA could produce sporadic low density hatchings in some areas.

• There may also have been some localised egg laying in mid-February in the Gilgandra and Nyngan area. If this occurred some localised medium instar nymphs could develop during March. However, there is unlikely to be a significant autumn generation of nymphs.

• There is a low probability of any significant immigration during March, given the low population levels in adjacent regions and the restriction of high densities of locusts to the southern Riverina and Hume LHPAs.    

Risk(s)

• There is a moderate probability of an increase in population to medium densities in some locations the Central West during the forecast period and of some low density sporadic laying of diapause eggs.       

Riverina

Riverina & Hume LHPA

Locusts and conditions

• The area affected by high density locusts has contracted to the eastern and southern margins of the region. Adult population densities increased in the Albury–Corowa–Walbundrie and Junee–Nangus areas of Hume LHPA during February, following the fledging of Bands of second generation nymphs. Several small areas of Concentration and swarm density adults were reported from these locations in late February. There were widespread Isolated–Scattered density adults throughout Riverina LHPA, with Numerous density adults in some areas.

• Surveys in Riverina LHPA identified Scattered–Numerous density adults in the Narrandera–Coolamon and Goolgowi–Hillston areas in mid-February, and Isolated–Scattered density adults in other areas.

• In the Wagga area sporadic Concentration and swarm density adults were reported in the Nangus–Junee–Illabo area in late February. Several small swarms were reported in the Albury–Walbundrie area in late February.

• There was some local migratory redistribution reported during late February, resulting in small swarms forming in the Corowa–Rennie area in late February.

• The level of Scelio wasp parasitism in the southern Riverina in summer may have contributed to the decline in adult population level between generations.

• There was widespread heavy rainfall (>40 mm) throughout Riverina and Hume LHPA areas during 1–7 February and further moderate–heavy falls (20–40 mm) in the eastern Riverina during the second and third weeks of the month.

 Forecast

• Fledging of second generation nymphs in the southern Riverina LHPA commenced at the end of January and continued into early February. This produced adults capable of egg laying from mid-February. If any egg laying occurred in mid-February, possible localised medium density hatchings could occur in mid-March. Any egg laying during March or April will produce mostly diapause eggs, which will not hatch until October.

• Adult activity could continue in the southern and eastern Riverina throughout March, with small swarms and egg laying persisting in some locations.

• The probability of immigration from Lachlan, Darling or Western LHPA areas is low, given the low population levels in other parts of NSW.

• Further local migration within the eastern and southern Riverina could occur during March and result in some localised high density egg laying. There is a low probability of any significant early autumn hatchings, and a moderate probability of localised hatchings in the southern Riverina in spring. There is a low probability of any significant immigration from Victoria.

Risk(s)

• There is a low probability of any significant third generation nymphs in the Riverina. There is moderate probability of adults persisting during March in the southeastern Riverina and of localised egg laying, which could produce some high density nymphs in spring.      

Northwest Slopes and Plains

Northwest LHPA

Locusts and conditions

• The overall population level in this region remained very low during February and there were no reports of this species.

• Surveys in mid-February identified occasional Isolated density adults in the Walgett–Narrabri area. No nymphs were detected during survey.

• There is a widespread Scattered–Numerous density population of several species of grasshoppers, including Oedaleus australis, and of spur-throated locusts throughout the Northwest LHPA area.

• There was light–moderate (<20–40 mm) rainfall in the Narrabri, Moree and Northern Slopes districts during 8–14 February.

Forecast

• The overall population level in this region remained very low during February and there were no reports of this species.

• Surveys in mid-February identified occasional Isolated density adults in the Walgett–Narrabri area. No nymphs were detected during survey.

• There is a widespread Scattered–Numerous density population of several species of grasshoppers, including Oedaleus australis, and of spur-throated locusts throughout the Northwest LHPA area.

• There was light–moderate (<20–40 mm) rainfall in the Narrabri, Moree and Northern Slopes districts during 8–14 February.       

Risk(s) 

• There is a low probability of a small population increase in this region during March or April. .     

Far West

Darling & Western LHPA

Locusts and conditions

• Adult population levels remained at low and medium densities during February, but light traps indicate continued migratory activity throughout the month. Surveys identified a Scattered density adult population in the Bourke and Wanaaring districts.

• Surveys were conducted in the Bourke, Cobar and Wanaaring districts in mid-February. There were Isolated–Scattered density adults in the Bourke–Fords Bridge area and south of Cobar, and Numerous density adult recorded near Bourke and Engonnia. There were consistent Scattered density adults in the Broken Hill–Fowlers Gap area in early February.

• The Fowlers Gap light trap recorded locusts on most nights during February, with high counts during the first week and moderate numbers 9–15 and 24–27 February. The White Cliffs light trap also recorded high numbers during the first week of February and during 10–11 February.

• There was widespread heavy rainfall heavy (>40 mm) throughout Western and Darling LHPA areas during the first week of February. There were further moderate-heavy falls (20–>40 mm) in the Bourke, Wanaaring and White Cliffs districts during 15–21 February. 

Forecast

• The continued light trap activity throughout January and February suggests adult population densities were maintained at higher levels than were detected by surveys in January. At Fowlers Gap the high catches indicate an almost continuous adult population, and high numbers were reported in the area for several days around the time of peak catches. Wind trajectories indicate possible movements in several directions, and peak catches were associated with troughs.

• Some egg laying may have occurred in the Tibooburra, Broken Hill or White Cliffs areas in late January or early February initiated by heavy rainfall at those times. This could have produced nymphs in some areas during February, and an increase in adult population is possible in March.      

Risk(s)

• There is a moderate probability that localised egg laying occurred in the western part of this region in late January or early February, which could contribute to a modest increase in adult population during March.      

Far South West

Western LHPA

Locusts and conditions

• The adult population remained at low levels in most of this region during February. Limited survey identified Isolated–Scattered density adults in the Ivanhoe–Hillston area.

• There was widespread heavy rainfall (>40 mm) throughout Western LHPA area during the first week of February and patchy light–moderate (20–40 mm) falls in the Balranald and Broken Hill areas during 15–21 February.      

Forecast 

• Heavy rainfall in early February may have initiated some sporadic egg laying in locust habitat areas. Given the generally low adult population density in the region, any egg laying is likely to result in only a moderate increase in adult population in the second half of March.

• Wind trajectories during February suggest immigration from the adjacent area of Northeast SA was unlikely. Given the generally low level populations in regions to the north, significant immigration is unlikely during March or April.        

Risk(s)

• There is a moderate probability of an increase in adult population during March or April as a result of localised egg laying in the first half of February.        

All locust activity should be reported to your Livestock Health and Pest Authority or Primary Industries, Industry & Investment NSW.
A toll–free call to the APLC can be made on 1800 635 962. An answering machine is attached for after–hours calls.

 

QUEENSLAND

Situation in February and forecast to April 2011

Southwest

Barcoo, Bulloo, Quilpie & Diamantina Shire

Locusts and conditions

• Adult population densities remained generally low in this region during February, despite heavy rains in recent months producing suitable soil and vegetation conditions for egg laying.

• Surveys during February identified Isolated–Scattered density adults in localised habitat areas in all Shires. Present density fourth instar nymphs were detected at one location near Quilpie.

• No Chortoicetes were recorded at the Nooyeah Downs or Birdsville light traps during February.

• There was widespread heavy rainfall (>40 mm) throughout the region during 8–15 January and light–moderate falls (<20–40 mm) in Quilpie and Barcoo Shires during 16–23 January.    

Forecast

• The heavy rainfall in mid-January and in Barcoo and Quilpie Shires in February would have produced suitable soil and vegetation conditions for locust breeding, but surveys detected little evidence of a nymphal generation. The likelihood of significant immigration into this region will decline during autumn. The probability of a large increase in population during autumn has therefore declined.

•  Some low density egg laying may have occurred in Barcoo or Quilpie Shire during February, which could result in an overall increase to in adult population to Numerous density in late March.       

Risk(s)

• There is a moderate probability that localised egg laying in February could produce an overall increase in adult numbers in late March in some areas .       

Locust activity should be reported to Biosecurity Queensland (Queensland Primary Industries and Fisheries). A toll free call to the APLC can be made on 1800 635 962. An answering machine is attached for after–hours calls.

Central West and Northwest

Longreach, Barcaldine and Blackall—Tambo Regional Shire. Boulia, Cloncurry, Flinders, Mckinlay, Mt Isa, Richmond & Winton Shire

Locusts and conditions  

• Population density remained at low levels during February.

•  APLC survey identified occasional Isolated density adults in Boulia and Winton Shires and in the Longreach and Barcaldine Regional Council areas in mid-February.

• The Longreach light trap recorded no Chortoicetes during February.

• Shires in the Northwest and Central West regions received light–moderate rainfall (<20–40 mm) during the first two weeks of February.      

Forecast

• There is likely to be a continuing low density population in this region during March, maintained by sporadic low density breeding.       

Risk(s)

• There is a low probability of a significant population increase during the forecast period.      

Central Highlands

Central Highlands and Isaac Regional Council

Locusts and conditions

• Population density remained very low during February and there were no reports of this species.

• APLC surveys in early February identified occasional Isolated density adults in the Clermont area and to the west of Springsure.

• Areas north of Emerald received light–moderate rainfall (<20–40 mm) during the first week of February and moderate–heavy falls (20–>40 mm) occurred south of Emerald during the second week of February.      

Forecast   

• There is unlikely to be any significant population increase in this region during autumn, given the very low population levels recorded.           

Risk(s)

• No risks are identified for this region during autumn              

South Central Queensland and Darling Downs

Balonne, Murweh and Paroo Shire. Roma, Dalby and Goondiwindi Regional Council

Locusts and conditions

• Population density remained generally low in this region, but there were Scattered–Numerous density adults recorded in the Paroo and Murweh Shires.

• APLC surveys in early February detected occasional Isolated density adults in Roma and Dalby Regional Council areas and Balonne Shire. There were more consistent Isolated–Scattered density adults in Paroo and Murweh Shires, with Numerous density adults in the Charleville–Wyandra area and east of Cunnamulla.

• There was light–moderate¬ rainfall (<20–40 mm) rainfall in Murweh and Paroo Shires in the first week of February, with locally heavy falls in Toowoomba Regional Council. Moderate–heavy (20–>40 mm) rain fell in Roma RC area and light falls elsewhere during 7–14 February. There were further moderate–heavy rains in Paroo Shire during 15–21 February.        

Forecast

• Population density remained generally low in this region, but there were Scattered–Numerous density adults recorded in the Paroo and Murweh Shires.

• APLC surveys in early February detected occasional Isolated density adults in Roma and Dalby Regional Council areas and Balonne Shire. There were more consistent Isolated–Scattered density adults in Paroo and Murweh Shires, with Numerous density adults in the Charleville–Wyandra area and east of Cunnamulla.

• There was light–moderate¬ rainfall (<20–40 mm) rainfall in Murweh and Paroo Shires in the first week of February, with locally heavy falls in Toowoomba Regional Council. Moderate–heavy (20–>40 mm) rain fell in Roma RC area and light falls elsewhere during 7–14 February. There were further moderate–heavy rains in Paroo Shire during 15–21 February.        

Risk(s)

• There is a moderate probability of medium population densities being maintained in parts of Paroo and Murweh Shires during autumn.        
              

Locust activity should be reported to Biosecurity Queensland (Primary Industries & Fisheries). A toll free call to the APLC can be made on 1800 635 962. An answering machine is attached for after–hours calls.

VICTORIA

Situation for February and forecast to April 2011

Locusts and conditions

• Fledging of second generation nymphs commenced in early February in the Wodonga–Shepparton area, in mid-February in areas around Bendigo and in late February in the Grampians and areas south of Horsham. Several swarms were reported in late February in the Yarrawonga–Cobram area and around Bendigo. Fledging will continue in areas around the Grampians in early March and some swarm formation is likely in areas as far south as Ararat.

• Areas affected by high density locusts during February were bounded by Wodonga–Euroa–Heathcote–Ararat–Horsham and Echuca. However Bands developed in areas as far south as Willaura and Cavendish and were at late instar stages in late February.

• Sporadic egg laying was reported near Tatura in late February.

• Surveillance by DPI Victoria identified a number of areas of Concentration density young adults in North Central Victoria in the second half of February.

• There was widespread heavy rainfall (>40 mm) in North Central Victoria during the first week of February and widespread moderate (20–40 mm) rainfall in Northwest and Southwest Victoria during 15–21 February.                

Forecast

• Fledging of Bands in the southern Wimmera and Grampians districts will continue in early March. A number of  swarms could develop in the Bendigo–Stawell–Ararat area during the first half of March.

• Adult activity will continue during March and further sporadic swarm formation is possible in the Wodonga–Shepparton and Bendigo areas.

• There is unlikely to be any significant autumn nymphal generation in Victoria. Sporadic egg laying such as reported near Tatura may produce localised nymphs in late March, and any further laying before mid-March could result in a proportion hatching and a proportion entering diapause, but the majority of eggs laid during March will enter diapause.

• A high proportion of eggs laid from mid-March to mid-April will enter diapause and not commence hatching until October. There is a moderate probability of localised high density nymphs developing in late spring, on a much smaller scale than spring 2010.

• Flooding in the Echuca–Swan Hill area is likely to have reduced nymphal survival in low-lying areas.

• There is a low probability of any significant immigration from western NSW during autumn, given the low population densities in most areas. Some movement to the south from the south-eastern Riverina are possible during March and could result in low numbers of locusts reaching cleared valleys in eastern Victoria. Locust numbers are already higher in North Central Victoria than the Riverina, so any immigration is unlikely to increase population levels. Some migratory exchange is also possible between western Victoria and adjacent areas of SA.

• Migratory movements of adult swarms within Victoria could extend the infestation area further south during March and April, and result in sporadic egg laying in the southwest of the state. Swarm egg laying is likely in parts of North Central Victoria and the southern Wimmera during March and April.     

Risk(s)

• There is a moderate probability of high density adult activity continuing into April in infested areas, and of significant autumn egg laying resulting in localised high density nymphs and some Bands during spring.                 

Locust activity should be reported to the Department of Primary Industries, Victoria. A toll–free call to the APLC can be made on 1300 135559. An answering machine is attached for after–hours calls. 

SOUTH AUSTRALIA

Situation in February and forecast to April 2011

Northeast, Far North, Northwest & Western Agricultural region

Locusts and conditions

• The nymphal generation the southern Northeast region extended from Morgan to Burra during February. Fledging in this area continued to mid-February and adult numbers increased to Concentration density in some areas. Elsewhere in the Northeast, Northwest and Far North regions adult densities remained at low densities.

• PIRSA carried out aerial control of approximately 17,000 ha of Bands in the Burra–Morgan area in early February.

• APLC survey in late February identified consistent Isolated–Scattered density adults from Hawker to Leigh Creek. There were occasional Isolated density adults north of Marree in Far North SA, and on the eastern side of the Flinders Ranges.

• The Oodnadatta light trap recorded locusts during 9–12 and 24–26 February.

• There was widespread heavy rainfall (>40 mm) in northern SA during the first week of February, and in the Coober Pedy area of the Northwest during 15–21 February.         

Forecast

• The probability of significant autumn immigration into the Northeast region had declined as a result of the generally low densities in northern SA. Some migration from the Morgan–Burra area was possible during February and may have contributed to adult numbers in adjacent regions.

• Some sporadic egg laying may have occurred in parts of the Far North and Northwest regions, following rainfall in the first half of February. This could produce localised areas of nymphs during March and an increase in adult numbers during April. A moderate population increase is possible during autumn, but is unlikely to present a significant immigration threat to southern regions.

• Some sporadic high density egg laying is possible in the Yunta–Burra area during March and the majority of any eggs laid after mid-March will enter diapause to hatch in spring.

• The continued light trap catches in SA and western NSW during February indicate further migratory redistribution in northern SA. Catches may indicate local nocturnal activity, but wind trajectories indicate a general westward trend to any long distance migrations.          

Risk(s)

• There is a moderate probability of sporadic high density egg laying in southern Northeast region during March, and of localised nymphs developing in spring.    
   

 Murray Valley & Southeast region

Locusts and conditions

• Nymph activity continued during February and many small Bands were reported in the Barossa Valley, from Eudunda to Gawler, along the lower Murray from Sedan to Murray Bridge and as far south as Coonalpyn. Bands were also reported in parts of the Murray Mallee district. Fledging commenced in mid-February and continued through to the end of the month. Concentration density adults and some small swarms developed in late February and adult activity will continue during March.

• Migratory movements in late February resulted in numerous reports of adults in Adelaide.

• Reports to PIRSA indicate Bands of late instar nymphs were still active in the Barossa Valley and southern Mallee area in late February and adult numbers had increased in many areas. Concentration and swarm density adults were reported from near Waikerie in the Riverland district and in part of the Barossa Valley. Mating of adults was reported in some locations.

• There was moderate rainfall (20–40 mm) rainfall over most parts of these regions during 15–21 February, which has maintained green pasture vegetation.     

Forecast

• Fledging will continue during early March and adult numbers are likely to continue to increase. Localised swarm activity is likely in infested areas during March and sporadic autumn egg laying is expected.

• There is a low probability of any significant third nymphal generation in these regions. The majority of eggs laid from mid-March to mid-April will enter diapause and not hatch until spring. A proportion of any eggs laid before that time could develop and hatch in late March and produce a low density nymphal generation, which may over-winter at mid-instar stages.

• Migratory movements of adult swarms could extend the infestation area further south or west to the Eyre Peninsula during March and April. The likelihood of migrations within the Murray Valley region will increase in during March, but the location of the infestation limits the probability of establishing a more widespread autumn breeding population. The most likely migration direction is to the south or west. Some immigration is possible from adjacent areas of western Victoria.      

Risk(s)

• There is a high probability of localised swarm formation in the Barossa Valley–Gawler area and parts of the Murray Mallee district during March. There is a moderate probability that autumn egg laying will produce localised areas of high density nymphs in spring.    

Locust activity should be reported to Biosecurity SA (PIRSA) at Locust Control Centres for  Northern areas and Eyre Peninsula — 8658 1456, or Riverland and Murray Mallee — 1800 833 451.
A toll–free call to the APLC can be made on 1800 635 962. An answering machine is attached for after–hours calls.

Map of Rainfall distribution 

 

Place Name Key for Rainfall Distribution Map

Queensland		Northern Territory
Bo	Boulia	AS	Alice Springs	B	Bourke
Br	Brisbane	TC	Tennant Creek	BH	Broken Hill
Bi	Birdsville			Du	Dubbo
Ch	Charleville	South Australia		Ha	Hay
CT	Charters Towers	Ad	Adelaide	Iv	Ivanhoe
Em	Emerald	CP	Coober Pedy	Na	Narrabri
Hu	Hughenden	Ma	Marree	Sy	Sydney
JC	Julia Creek	Oo	Oodnadatta	Ti	Tibooburra
LH	Lawn Hill	PA	Port Augusta	Wy	West Wyalong
Lo	Longreach	Yu	Yunta
No	Normanton
Qu	Quilpie
SG	St. George	Ho	Horsham
Ur	Urandangi	Me	Melbourne
Wi	Windorah	Mi	Mildura

Glossary of terms and abbreviations used in the Locust Bulletin

Where higher densities occur a large proportion of the regional population is concentrated in small areas with lower densities elsewhere, so the high densities cannot be extrapolated across the area of an entire region. Typically a range of density classes is found within surveyed regions and higher densities occur where habitat conditions are favourable. More detail is available about terms and descriptions used here.

Nymph Densities	Number per m2
Present (P)	1        —    5
Numerous (Num)	6        —    30
Sub–band (SB)	31      —    80
Band (B)	>   80
Adult Densities	Number per m2	Number per hectare
Isolated (Iso)	—    0.02	< 200
Scattered (Scat)	0.03   —    0.1	>200   —   1000
Numerous (Num)	0.2     —    0.5	>1000  —  5000
Concentration (Conc)	0.6     —    3.0	>5000  —  30,000
Low Density Swarm (LDS)	4.0     —    10	>30,000 — 100,000
Medium Density Swarm (MDS)	11      —    50	>100,000 — 500,000
High Density Swarm (HDS)	>   50	>500,000
General Density Classes	Nymph Densities	Adult Densities
very low, occasional	Nil—Present	Nil—Isolated
low	Present—Numerous	Isolated—Scattered
medium	Numerous—Subband	Scattered—Numerous
high	Bands	Concentration—Swarms

Reporting locust infestations

It is important that all locust activity is reported as soon as possible to your Department of Primary Industries (Agriculture) or to the Australian Plague Locust Commission.

State	Authority to report locust infestations to
New South Wales	Livestock Health and Pest Authority (LHPA) or Primary Industries, Industry & Investment NSW
Queensland	Biosecurity Queensland, Queensland Primary Industries & Fisheries
South Australia	Primary Industries & Resources South Australia (PIRSA) Plant Health
Victoria	Department of Primary Industries, Victoria — Plague Locust information

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

Free call (Canberra) — 1800 635 962 (24 hours)
Fax (Canberra) — (02) 6272 5074
Email: Locust Report

 

Forecasting Districts used in the Bulletin

 

General regions referred to in the Bulletin

Location of APLC light traps (black circles).
Locust habitat areas shaded.