Locust Bulletin September 2009

The printed version of the Locust Bulletin is produced monthly 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 September 2009 - table of contents

General locust situation
Australian plague locust situation
Australian plague locust map August 2009
Forecast development dates
Potential area of spring infestation in NSW
Rainfall winter 2009
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 August and outlook to mid-October 2009

Australian Plague Locust
Spur-throated Locust
Migratory Locust

A large nymph infestation is expected to develop in Central West New South Wales during spring. Hatchings began in the Coonamble–Quambone and Nyngan–Tullamore areas during the last week of August. Above average temperatures during July and August resulted in the completion of egg development and hatching several weeks earlier than would be expected with average temperatures. First instar nymphs at medium–high densities were reported from the Quambone, Baradine, Come-By-Chance and Nyngan areas and hatchings will increase in early September throughout the Central West Livestock Health and Pest Authority (LHPA) area. Many hopper bands requiring control measures are likely to develop during September.  Fledging of nymphs could begin in the second week of October in the Coonamble area.

The outlook for spring is for high density nymphs to develop in the Coonamble–Baradine, Quambone–Warren, Nyngan–Tottenham and Tullamore–Peak Hill areas of the New South Wales Central West during September. Diapause eggs laid near Parkes–Peak Hill in March are expected to hatch from late September. The low numbers of mid-instar nymphs at many locations during July and August are likely to have over-wintered as nymphs.

Parts of far western New South Wales could also produce nymph activity during spring, following swarm development and egg laying in late March. A nymph infestation is possible in the Wilcannia–Broken Hill and Ivanhoe–Menindee areas, where bands could develop in some locations. Early surveys indicate the current dry conditions have reduced the likelihood of significant nymph activity in the Tibooburra–Packsaddle area, but conditions are more favourable in the Ivanhoe-Wilcannia area.

The population in western Queensland declined to low levels during autumn. Surveys in late August in the Central Highlands and South Central Queensland identified a low density adult population. There is unlikely to be any significant population increase before October in Queensland, but some winter breeding may have occurred in the Windorah–Quilpie area following heavy rain in June.

Localised egg laying may also have occurred around the northern Flinders Ranges in the Far North of South Australia in late March, which could produce some nymph activity in September.

No significant locust activity is likely in Victoria during spring, but low density adults were reported near Echuca and Tungamah in autumn.

Western Australia reported medium–high density locusts and egg laying in a number of Shires of the Central and Western Agricultural Regions during April. Breeding during autumn is likely to produce a nymph infestation in spring. Hatchings should begin around Southern Cross in mid-September and extend into October in the Lake Grace, Salmon Gums and Gnowangerup areas.

•  Spur-throated locust                                                                               Austracris guttulosa

There are numerous swarms west and north of Winton, and around Dajarra, Richmond and Julia Creek in Northwest Queensland. Reports of swarms damaging trees were received from these areas in July and August. The Julia Creek light trap caught locusts throughout June and August. Surveys in August identified a widespread Isolated density adult population throughout the Central West, Central Highlands and South Central Queensland, and in the Northwest Plains of New South Wales.

The development of over-wintering swarms is common in Northwest Queensland after immature adults redistribute in late autumn. These swarms feed on tall grasses and trees during winter. There are also likely to be a number of swarms in the Queensland Gulf and parts of the Barkly Tableland at this time of year.  Adults migrate and disperse to commence breeding from the start of the northern wet season.

• Migratory locust    Locusta migratoria

Surveys during August identified very few adults of this species, with only occasional Isolated density adults near Goodooga in the NSW Northwest LHPA.  Vegetation conditions are generally dry in the Central Highlands and South Central Queensland and surveys in these regions in late August did not detect any adults or nymphs.

3 September 2009

• Australian plague locust situation

  New South Wales
  Queensland
  Victoria
  South Australia

Distribution of Australian plague locusts: 1 August to 2 September 2009

Nymphal density

Present
Numerous - Subband
Band

Adult density

Nil - Isolated
Isolated - Scattered
Scattered - Numerous
Numerous - Concentration
Swarms present

Densities estimated for areas of locust habitat, based on survey and reports. 

Forecast development dates for indicative locations in NSW, Queensland and South Australia

Location - NSW	Egg laying	Hatching	Mid-instar	Fledging
Coonamble-Quambone	10 May	28 August	16 September	10 October
Peak Hill-Narromine	24 March	30 September	15 October	5 November
Walgett-Narrabri	1 May	18 August	6 September	1 October
Bourke-Enngonia	1 May	11 August	29 August	25 September
Tibooburra-Wanaaring	15 April	10 August	29 August	23 September
Broken Hill-Wilcannia	12 April	25 August	11 September	5 October
Ivanhoe-Menindee	26 March	20 August	9 September	5 October
Nyngan-Tullamore	10 May	1 September	18 September	11 October
Location - Qld	Egg laying	Hatching	Mid-instar	Fledging
Cunnamulla-Charleville	12 April	15 August	29 August	22 September
Quilpie-Eromanga	12 June	24 August	6 September	27 September
Tambo-Augathella	12 June	23 August	5 September	27 September
Location - SA	Egg laying	Hatching	Mid-instar	Fledging
Moolawatana-Marree	15 April	16 August	6 September	28 September
Hawker-Yunta	15 April	10 September	27 September	19 October

Forecast dates in the table above are based on development models for possible egg laying of known adult populations and assuming sufficient soil moisture for direct development. Development dates are estimated from recorded temperatures at these locations to 30 August.  Hatching date indicates the start of the emergence of the majority of the nymphal population. Hatching will continue for several weeks after these dates. Forecast dates will be updated regularly.

 

Map of possible spring infestation area in Central West NSW

Area shaded blue shows the region where high density nymphs
could develop during spring, based on adult distribution and reports of egg laying.
NSW LHPA boundaries shown in black

NEW SOUTH WALES

Situation for August and forecast to mid-October 2009

Central WestLachlan, Central West & Central North LHPA

Locusts and conditions

• Hatching of eggs laid during May began in late August, several weeks earlier than would be expected based on average temperatures for this region. By the end of August, Numerous density early instar nymphs were identified in several locations in the Coonamble district. Many Bands are likely to develop throughout the Central West LHPA during September.
  
  
• LHPA staff identified hatchings at egg bed locations and surrounding properties at Quambone from 26 August. APLC surveys on 29 and 30 August identified Numerous–Subband density first instar nymphs in this area.  Lower density first instar nymphs were found at several locations in the Central West LHPA, including the Warren–Nyngan and Coonamble–Quambone areas.
  
  
• Surveys on 31 August identified Band density hatchings between Coonamble and Baradine at a reported egg bed site.
  
  
• Isolated-Scattered density adults in the region may have fledged from over-wintering nymphs.
  
  
• Low density mid-instar nymphs identified at a number of locations throughout Central West and northern Lachlan LHPA areas since July are likely to have over-wintered at that stage.
  
  
• There may be some hatchings in the Tooraweenah–Warrumbungle area at the western edge of Central North LHPA during September.
  
  
• There was moderate–heavy (20->40 mm) rainfall in the Central West LHPA in early June and several periods of light rainfall (<20 mm) during July. There was light rainfall in the eastern part of the region during the last week of August. Pasture vegetation remains green, but is beginning to dry off in many areas.        

Forecast

• Hatching began in the Coonamble district during the last week of August. This is up to three weeks earlier than would have occurred under average temperatures. Maximum temperatures in northern NSW during August were 3–4 degrees above average and minimum temperatures were also above average in June and July. Eggs would have been at a late stage of development during August and several near 30o days resulted in the early hatchings.
  
  
• Hatching will continue during the first half of September throughout the Central West and many small Bands are likely to develop. Widespread hatchings are likely In the Coonamble area as far south as Collie and as far north as Come-By-Chance. Hatchings are expected to follow in the Nyngan–Tottenham–Dandaloo and Tullamore–Albert areas during September.
  
  
• Examination of eggs from egg beds laid in mid-May in the Coonamble–Quambone area indicates that the level of parasitism by Scelio spp. wasps is unlikely to exceed 10%.  The average number of nymphs hatching per pod from these layings is <20. However, given the number and extent of egg beds throughout the region, a large spring nymphal population is still expected to develop.
  
  
• Fledging of early hatched nymphs could begin before mid-October and there is the potential for a number of swarms to develop in the Central West LHPA area after that time.
  
  
• Hatching from egg beds in the Parkes–Peak Hill area of Lachlan LHPA, which were laid during March and have been in winter diapause, is likely to commence at the end of September, but nymphs could emerge earlier if above average temperatures continue.  

Risk(s)

• There is a risk of localised damage to crops from hopper Bands developing in adjacent pasture areas during September in the Central West and northern Lachlan LHPA. 

Riverina

Riverina & Hume LHPA

Locusts and conditions

• No significant population is expected in the Riverina region during spring, but some sporadic egg laying may have occurred in the Narrandera and Hay districts in late autumn. Low-medium density nymphs could develop in these areas in late September. 
  
  
• There were several periods light rainfall (<20 mm) in eastern Riverina LHPA and across Hume LHPA area during June and July. There were further light rains in these areas during the last two weeks of August. There is spring pasture growth in the eastern Riverina and Hume LHPA areas.     

 Forecast

• Low–medium density nymphs may develop in some locations in the Narrandera–Morundah and the Goolgowi–Gunbar areas from late September. Nymphs would reach mid-instar stage in mid-October and fledge in early November.
  
  
• There is unlikely to be any immigration from the Central West of NSW before November. 

Risk(s)

• There is a low risk of some nymphs developing in parts of the Narrandera district during October.    
   

Northwest Slopes and Plains

Northwest LHPA

Locusts and conditions

• Surveys were conducted in the Walgett, Moree, Narrabri, Brewarrina and Northern Slopes districts in late August. Low density adults occurred in some locations, but few nymphs were detected. There was a report of Band density first instar nymphs from the Come-By-Chance area on the southern edge of the Northwest LHPA at the end of August.
  
  
• Surveys identified occasional Isolated density adults in the Brewarrina–Goodoga and Warialda areas and Isolated–Scattered density adults in the Collarenebri–Mungindi area.
  
  
• There were reports of nymphs from the Burren Junction area at the end of August.
  
  
• There were several periods of light rainfall (<20 mm) during June and early July. There were further light rains during the last week of August. Pasture conditions are generally dry.        

Forecast

• The infestation south of Come-By-Chance is the northern extension of the large population in the Coonamble district. Most eggs will hatch in early September and Bands are expected to develop in the Hollywood–Brantwood area where swarms were reported laying in autumn. Nymphs will fledge in this area from early October and a few swarms could develop in the second half of October.
  
  
• There is unlikely to be any significant immigration of adults from the Central West before late October.             

Risk(s) 

• There is a risk of localised crop and pasture damage from hopper Bands developing in the area south of Come-By-Chance during September.  
    

Far West

Darling & Western LHPA

Locusts and conditions

• Locust numbers were low in areas surveyed in late August. There were Isolated density adults in parts of Darling LHPA, but none identified in Western LHPA.
  
  
• APLC surveys in the Tibooburra, White Cliffs, Wanaaring and Broken Hill areas in late August identified very few locusts. Present density third instar nymphs were found at one location near Cobham in a drainage area.  No locusts were found in the Wanaaring or White Cliffs district.
  
  
• Surveys in the Bourke area identified occasional Isolated density adults in the Enngonia and between Bourke–Yantabulla areas. There were Present density third instar nymphs between Bourke and Fords Bridge.
  
  
• No locusts were caught in the Fowlers Gap light trap during August.
  
  
• There was moderate–heavy rainfall (20->40 mm) in the Bourke, Cobar and Wanaaring districts in late June, and further light rainfall (<20 mm) in these areas in mid-July.  Conditions are dry in Western LHPA, while some green pastures and forbs remain in the Bourke and Cobar districts.             

Forecast

• Although several swarms were identified in the Milparinka area in mid-April, August surveys did not indicate significant autumn breeding occurred in that area. However, the dry conditions could have resulted in quiescence of eggs, which could hatch if there is moderate rainfall during September.
  

• The occasional mid-instar nymphs in the Bourke–Fords Bridge area are likely to have hatched from autumn laid eggs. These could represent a more widespread nymph population in the Louth area.
  

• Some hatching could occur in the Wilcannia–Broken Hill area in late-August September, following swarm activity in that area in April.
  

• There is unlikely to be any significant immigration in this region before November.          
  

Risk(s)

• No significant population was detected in this region during August and no specific risks are identified for the forecast period.   
     

Far South West

Western LHPA

Locusts and conditions

• Surveys at the end of August in the Broken Hill–Wilcannia and the Ivanhoe–Pooncarie areas identified a very low density adult population. Hatchings began from known egg beds in the Dalmorino area at the start of September.
  
  
• Surveys in late August identified occasional Isolated density adults in the Wilcannia–Menindee and Ivanhoe-Pooncarie areas. No nymphs were found at known egg beds on Dalmorina on 2 September.
  
  
• There were light rains in the Broken Hill and Hillston districts in the second half of July, and further light falls in the Broken Hill and Balranald-Wentworth areas in the last week of August.               

Forecast 

• Hatching of diapause eggs in the Dalmorino area had not commenced at the start of September, despite temperature driven models suggesting emergence at this time. Hatching could be delayed by quiescence in areas where there was insufficient soil moisture to allow complete egg development. If eggs are in quiescence, hatching would occur ten days after the next rainfall. Examination of diapause eggs from Dalmorino suggests that the level of parasitism by Scelio spp. wasps is <10%.
  
  
• The potential nymph infestation could to produce localised medium density nymphs in the Broken Hill, Wilcannia, Menindee and Ivanhoe districts in September, with Bands developing in some areas.              

Risk(s)

• There is moderate likelihood of high density nymphs developing in the Broken Hill–Wilcannia and Ivanhoe–Menindee areas during September and October.      
•   
  

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 for August and forecast to mid-October 2009

Southwest

Barcoo, Bulloo, Quilpie & Diamantina Shire

Locusts and conditions

•  No survey was conducted during August.
  
  
• The Nooyeah Downs and Birdsville light traps recorded no locusts during August.
  
  
• There was heavy rainfall (>40 mm) in the Windorah–Quilpie area during the first week of June, but no significant rainfall since that time. There is some localised green vegetation remaining in this area, but conditions are dry in Bulloo and Diamantina Shires.           

Forecast

• There may have been some breeding activity in the Windorah–Eromanga–Quilpie area following heavy rainfall in May and early June. Breeding in early June would have produced diapause eggs that would have hatched during August. There could be medium density nymphs in some areas during September and fledgling adults at the end of September.    
  

Risk(s)

• There is a low risk of a significant nymph population developing in the Windorah–Eromanga–Quilpie area during September.
  

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  

• Surveys were conducted in the Longreach, Barcaldine and Blackall-Tambo Regional Council areas of the Central West region in late August. Population density was low and no nymphs were identified.
  
  
• Surveys in August identified occasional Isolated density adults in the Longreach and Blackall-Tambo Regional Council areas.
  
  
• No locusts were caught in the Longreach or Julia Creek light trap during August.
  
  
• There was moderate–heavy rainfall (20–>40 mm) in the Tambo area in June, but little further rainfall in this region during winter. Vegetation conditions were mostly dry in late August.     
          

Forecast

• The continuing low population density in the Central West suggests there was no significant locust breeding in this region during late autumn or winter. If breeding occurred in early June following widespread rains, there could be fledging nymphs and young adults at medium densities in late September and early October, particularly in the southern Central West.

Risk(s)

• There is a low risk of a population increase in this region in spring as a result of egg laying following rains during in May and June.

Central Highlands

Central Highlands and Isaac Regional Council

Locusts and conditions

• Surveys were conducted in Central Highlands and Isaac Regional Council areas at the end of August. Low density adult locusts were identified by surveys and there were no reports of locust activity.

• Survey during 28–30 August detected only occasional Isolated density adult locusts in the Clermont–Twin Hills area of Isaac Regional Council.

• There was light–moderate rainfall in late June in this region, but little rainfall during the rest of winter. Pasture vegetation is largely dry.

Forecast   

• Given the very low population level in the region, there is unlikely to be any increase in population before November. 

Risk(s)

• No significant risks are identified for this region during the forecast period.        

South Central Queensland and Darling Downs

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

Locusts and conditions

•  Surveys in late August detected a low density adult population in South Central Queensland.
  
  
• Surveys were conducted in parts of Paroo, Balonne and Murweh Shires, and in Roma, Goondiwindi and Dalby Regional Council areas.  There were Isolated density adults in the Mitchell–Roma and in the Goondiwindi Regional Council area. In the Dalby Regional Council area there were Isolated–Scattered density adults along with Present density third instar nymphs between Miles and The Gums. Very few locusts were found in Murweh and Paroo Shires, except Isolated–Scattered density adults south of Cunnamulla near the NSW border.
  
  
• There were moderate–heavy (20–>40 mm) falls in Murweh and Paroo Shires in early June, and light rains (<20 mm) in Goondiwindi and Balonne Shires, and the Goondiwindi and Dalby Regional Council areas in mid-July. Pasture conditions were mostly dry in these regions in late August. 
              
  Forecast   
  
• Vegetation and soil conditions are mostly unsuitable for locust breeding in this region. However, nymphs found in the Tara–The Gums area indicate that some breeding occurred following rains in July.
  
   Any breeding in Paroo or Murweh Shire in early June could produce fledgling adults during September. 

Risk(s)

• No significant population increase is likely in these regions during September and October.
              

Locust activity should be reported to Biosecurity Queensland (Primary Industries &Forestry). 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 August and forecast to mid-October 2009

Locusts and conditions

• Locust population density remains low in northern Victoria. There is unlikely to have been any significant autumn breeding. 
  
  
• Low numbers of adult locusts were reported from several areas during April, including Gunbower Island, Strathallan and Tungamah.
  
  
• There were periods of light–moderate rainfall (<20-40 mm) in northern Victoria during June, in mid-July and during the last week of August.              

Forecast

• If any egg laying occurred where low density populations were identified in autumn, hatching would occur from early October.
  
  
• There is unlikely to be any significant immigration before November.       
      

Risk(s)

•  Localised hatching of diapause eggs could occur in the Echuca and Tungamah areas during October. No significant risk to agriculture is likely.             

Locust activity should be reported to the Department of Primary Industries, Victoria. A toll-free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls. 

SOUTH AUSTRALIA

Situation for August and forecast to mid-October 2009

Far North, Northwest, Northeast & Western Agricultural region

Locusts and conditions

• No survey was conducted during August and there have been no reports of locust activity. 
  
  
• The Dulkaninna and Oodnadatta light traps recorded no locust activity during August.
  
  
• There were several periods of light–moderate rainfall (20–40 mm) in southern parts of SA during June and July. During the last two weeks of August there was further patchy light rainfall (<20 mm) in the northern Flinders Ranges area and the Northeast and Western Agricultural regions. Conditions are dry in most areas north of the Flinders Ranges.    
          

Forecast

•  Sporadic hatchings are possible from early September around the northern Flinders Ranges in the Far North region, although vegetation conditions are dry in most areas. Any nymphs are likely to be found along drainage lines in the Moolawatana–Murnpeowie and Marree–Lyndhurst areas.
    
      

Risk(s)

• There is a low risk from medium density nymphs developing in the northern Flinders Ranges area during spring.              

Locust activity should be reported to Primary Industries & Resources, South Australia.
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		New South Wales
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	Victoria
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.