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Locust Bulletin May 2008
The HTML page below follows the structure of the Bulletin with the 'General Locust Situation', the 'Australian Plague Locust Situation' for regions in each state and the maps. The Bulletin is also available for download as a PDF document.
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Locust Bulletin May 2008 - table of contents
General locust situation
Australian plague locust situation
Australian plague locust map April 2008
Spur-throated locust map April 2008
Map of Riverina showing possible area of bands in spring
Rainfall events April 2008
Terms and Abbreviations used in the Bulletin
Map of forecast regions used in the Bulletin
General situation in autumn 2008 and outlook to spring 2008
Australian Plague Locust
Spur-throated Locust
Migratory Locust
The adult locust population increased to high densities in the eastern Riverina of New South Wales during March. This was primarily the result of the aggregation of locusts that fledged in this region in late February and early March, but some migration from the Central West in early March may have contributed to the increase. Concentration and swarm density adults with developed eggs were widespread in Murray, Wagga and the western part of Hume Rural Lands Protection Board (RLPB) districts, but numbers had declined to medium densities by the end of April. Egg laying began in the Riverina in late March and continued during April and into early May. A potentially serious nymphal infestation with many bands is therefore expected to develop in the Riverina in October and November.
Redistribution of adults during April produced a widespread medium density population in the southern Central West and Riverina of New South Wales, and in North Central Victoria at the start of May. Some egg laying has occurred in all these regions and more localised medium density hatchings, with bands developing in some locations, is likely in spring. Highest density spring hatchings are expected in Murray, Wagga, southern Narrandera, western Hume and Riverina RLPB districts, where hatchings will begin in early October with a peak in mid-October. Landholder identification and control of small bands on farmland will be critical to minimising the impact of locust nymphs on crops and pastures during October and November.
Locust density remained low in the Northwest Plains and northern part of the Central West of New South Wales during April, following the decline in early March. Medium to high density adults developed in southern Forbes and Condobolin, and in Molong RLPB districts, and extended into the western edge of Gundagai and Young RLPB districts. Spring hatchings from autumn egg laying will begin in late September in these areas. In the Far West and Far Southwest regions of New South Wales nymphs fledged in the Wanaaring–Tibooburra area and the Menindee–Ivanhoe area during March, which produced small areas of high density adults in the Wilcannia–White Cliffs and Sayers Lake–Darnick areas in early April. Egg laying may have occurred in the White-Cliffs area during April.
In Victoria reports of adult locusts between Echuca and Wodonga in North Central Victoria began in late March. The population in Victoria is primarily the result of migration from adjacent areas of the Riverina in March and April, but low numbers of adults could have migrated into this region and bred at low densities from as early as January. There were further migrations of adult locusts into Victoria during April, and surveys identified a widespread medium density population in the area bounded by Wodonga, Wangaratta, Rushworth and Echuca, with up to Concentration density adults in some locations. There were also reports west of Echuca, and as far south as Nhill in Northwest Victoria in late April. The presence of occasional nymphs indicates egg laying occurred in some locations in Victoria from late March and continued during April. Medium density nymphs and some small bands are likely to develop in November.
Locust densities in most regions of Queensland and northern South Australia declined to very low levels during April apart from some low density adults and occasional nymphs near Cunnamulla in Paroo Shire, South Central Queensland.
There was a widespread medium density adult population throughout the Central Highlands and Central West Queensland, with up to Concentration density immature adults in several shires during March. Surveys in April indicate a redistribution of the immature adult population, with densities declining in the Central West and increases to Scattered–Numerous density in Southwest Queensland and in the Paroo Shire. There were Isolated–Scattered density adults in other parts of south Central Queensland and the Darling Downs. Fledging of this summer generation was completed by the end of March and no nymphs were found on survey. High density adults were reported from southwest of Springsure in Bauhinia Shire during April.
Longreach light trap recorded high numbers of locusts during 5–17 March, with a peak of over 800 on 8 March, and during 7–9 April. The light trap at Julia Creek recorded over 50 locusts on 13 and 14 March and low numbers in mid-April. The activity at Longreach may reflect redistribution and migration of the population of young adults in Central West Queensland. An increase in the numbers of adults in the Far West and the Northwest Plains of NSW was reported at the start of April. White Cliffs light trap caught low numbers on 31 March and in the first week of April, indicating redistribution and migration of the immature adult population. Surveys in April in New South Wales indicated a population increase with widespread Isolated–Scattered density counts in the Far west and Northwest Plains.
Some small swarms of adults may develop in the northern part of Central West Queensland, which is usual for this time of year. There was a report of swarms in the Richmond area in early May, and other swarms are likely to develop in the Queensland Gulf Country during winter. Immature adults often redistribute during autumn and form overwintering swarms, which may feed in green vegetation areas and roost in trees.
In early March small Bands of mid-instar nymphs were identified by Biosecurity Queensland staff in sorghum crops on properties in the area between Emerald and Springsure. Fledging occurred in late March. Surveys during April identified a consistent low density adult population in the area around Emerald and Springsure. In mid-April Biosecurity Queensland carried out 378 ha of control of swarms on a property southeast of Capella in Peak Downs Shire. While the risk of a significant infestation developing this locust season has declined, the seasonal outlook for above-average rainfall during autumn in part of eastern Queensland could allow further gregarious breeding in parts of the Central Highlands.
18 May 2008
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Australian plague locust situation
Distribution of Australian plague locusts: 1 April to 10 May 2008
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.
Distribution of Spur-throated locusts: 1 April to 10 May 2008
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.
NEW SOUTH WALES
Riverina
Hay, Hume, Murray, Narrandera, Riverina & Wagga Wagga RLPB
Locusts and conditions
- The adult population declined from swarm to medium densities in most areas by the end of April, but high densities persist along roadsides, and in pastures and lucerne crops in some parts of the eastern Riverina. There have been some reports of damage to early cereal crops. Egg laying began in late March and the remaining adult females at the beginning of May still had developed eggs, so multiple egg pods are likely to have been laid. Significant autumn breeding has occurred in the eastern Riverina and Bands are likely to develop in these areas during mid-October and November. There has been more localised breeding in parts of Hay and Riverina RLPB areas.
- Aerial surveys in Murray RLPB in early April identified widespread Concentration and some swarm density adults, but the potential targets were insufficient to initiate an APLC aerial control campaign.
- Low density early and mid-instar nymphs were identified in a number of locations in early May. These nymphs are likely to represent a small proportion of the eggs laid in March, which developed directly as a result of above average temperatures during that month. The majority of eggs will now be in diapause and will hatch during October. High density adults and egg laying also occurred in northern Wagga RLPB near Temora and also extended into the western part of Gundagai and Young RLPB areas, with egg beds at Illabo, near Junee, and Numerous–Concentration density adults between Bimbi and Stockinbingal.
- Surveys in early April identified several areas of Concentration and Low density swarm adults in the Lockhart–Urana, and the Finley–Berrigan areas of Murray RLPB, and also in the Rand–Walbundrie area in Hume RLPB district. By early May adult densities had declined in these areas, with consistent Scattered–Numerous density counts. However, Numerous and Concentration density adults were found in green vegetation between Wagga and Narrandera. There were also Concentration density adults at one location southwest of Mathoura in Riverina RLPB, near ‘Wilurah’ in Hay RLPB and near Grong Grong in Narrandera RLPB in early May. Scattered–Numerous density adults occurred in most other areas of these districts. Other species (Oedaleus, Aiolopus, Pycnostictus spp.) were mixed with locusts at some locations.
- There were light rains (<20 mm) throughout the region during the last week of April. Pasture vegetation is drying in most areas but localised green areas remain in Narrandera, Hume and Wagga RLPBs.
Forecast
- The widespread population in Murray, Wagga and Hume RLPB districts are the result of aggregation of adults following the local fledging of nymphs in late February and early March. Immigration from the Central West and Northwest Plains may have contributed to the population. Occasional second and third instar nymphs in early May indicate egg laying from mid-March in some locations. Those nymphs probably represent a small proportion of the total eggs, which developed directly, but the majority of eggs will now be in diapause.
- Early hatchings may appear from the beginning of October in Murray, Narrandera and Riverina RLPB, with peak hatchings from the second week of the month. The peak at Wagga will be the third and last week of October. Peak hatching may be delayed where dense pastures reduce soil temperatures. Eggs laid in Hay and northern Narrandera RLPBs will emerge in late September. The map below shows the area within which Bands are expected to develop.
- Samples of high density adults in early May showed many females with developed eggs, indicating multiple pods are likely to have been laid. Later clutches in autumn may contain fewer eggs, but the likelihood of three pods being laid by many females would indicate that many dense Bands will develop in some areas.
Risk(s)
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There is a high risk that egg laying in the eastern and southern Riverina during autumn will produce numerous Bands in Murray, Wagga, Hume and southern Narrandera and Riverina districts in spring. Peak hatchings will occur in mid-October, with nymphs fledging after mid-November. Some swarms could develop in these areas from early December.
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There is a risk of some damage to early winter cereal crops, however adult numbers are likely to decline to low densities during May.
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Landholder identification and control of small bands on farmland will be critical to minimising the impact of nymphs on crops and pasture during spring.
- A significant proportion of the nymph infestation in the eastern Riverina is likely to be in small bands, or in locations which are otherwise unsuitable for aerial treatment.
Map showing the area in the NSW Riverina and Central West within which development of nymphal Bands is likely during spring. Estimate based on known distribution of high density adults, egg beds, NSW RLPB and DPI-Victoria reports during autumn.
All locust activity should be reported to your Rural Lands Protection Board or NSW Department of Primary Industries.
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
Coonabarabran, Coonamble, Condobolin, Forbes, Molong, Nyngan & Dubbo RLPB
Locusts and conditions
- The adult population in the northern part of this region declined to low densities during March and April. Adult numbers increased in parts of Forbes, Molong and southern Condobolin RLPB districts during late March and April, with reports of flying adults and egg laying in some locations. There appears to have been a general movement of adult locusts to the east and south, with a build-up to high density in pasture habitats on the western side of ranges. Adults persisted at medium–high densities in some locations in early May.
- Surveys during April and early May identified consistent Isolated–Scattered density adult locusts in Nyngan, Coonamble and Dubbo RLPB areas, with Numerous density adults near Narromine at the end of April. Survey in early May in parts of Condobolin and Forbes RLPB areas found consistent Scattered–Numerous density adults in many areas. Concentration–swarm density adults were located in one area between Tullibigeal and Ungarie in Condobolin RLPB. There were occasional Present density second and third instar nymphs in some locations.
- There were several reports of increased locust activity in late March, and adult numbers increased to Numerous to Concentration densities in the Cumnock-Euchareena area of southern Dubbo RLPB, the Kerrs Creek–Boomery area of Molong RLPB, and the Garema–Bimbi area of Forbes RLPB. Adults persisted at Numerous density in southern Forbes RLPB around Bimbi in early May.
- There was a report of adult locusts in the Mullaley area of Coonabarabran RLPB during March, and in early May nymphs were reported from the same area.
- There were light rains (<20 mm) in Coonabarabran RLPB during 16-22 April and light rains in Condobolin, Forbes and Molong RLPBs, with moderate falls in Gundagai and Young RLPBs, in the last week of April.
Forecast
- The reported increase in adult population in the Molong and Forbes RLPB districts during March was primarily the result of adult migration from the northern districts of the Central West, although reports from Molong RLPB area included nymphs, which indicates some local breeding in February. There was a general drift of adult locusts to the east and south, with adult numbers gradually increasing to Numerous and Concentration densities in some locations during April. While adult numbers had declined in most areas by early May, the above average temperatures during March and the lack of frosts have resulted in persistence of adults at Numerous density in pasture paddocks and along roadsides. Samples from high density adults in early May showed developed eggs, so repeated egg laying by females is likely to have occurred in some locations.
- Egg laying occurred in parts of southern Dubbo, Molong, Condobolin and Forbes RLPBs during March–April. Most eggs laid after mid-March would enter diapause, with hatching extending from late September through October. The April distribution of adults is an indicator of the extent and density of nymphs in spring. Bands are likely to develop in some parts of southern Condobolin and Forbes RLPB, and western Molong, Young and Gundagai RLPBs. The map above shows the area within which Band development is likely during spring.
Risk(s)
- There is a moderate risk that medium–high density autumn egg laying has occurred in a number of RLPB districts in the southern part of the region during autumn. There is likely to be a significant nymphal population in some areas during spring, particularly southern Forbes and Condobolin RLPBs and western Molong, Young and Gundagai RLPBs. Pasture vegetation has dried off in many areas, but green vegetation remained in eastern areas during April.
- Landholder identification and control of small bands on farmland will be critical to minimising the impact of nymphs on crops and pasture during spring.
- A significant proportion of the nymph infestation in the Central West is likely to be in small bands, or in locations which otherwise are unsuitable for aerial treatment. .
- Landholder identification and control of small bands on farmland will be critical to minimising the impact of nymphs on crops and pasture during spring.
- A significant proportion of the nymph infestation in the eastern Riverina is likely to be in small bands, or in locations which otherwise are unsuitable for aerial treatment.
All locust activity should be reported to your Rural Lands Protection Board.
A toll-free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls.
Northwest Slopes and Plains
Moree, Narrabri, Northern Slopes & Walgett RLPB
Locusts and conditions
- Following the fledging of nymphs and the formation of some small swarms in the Moree and Walgett RLPB districts in late February, surveys in early March indicated that adult numbers had declined to medium densities in these areas, and further surveys in April identified a low density population throughout this region.
- Surveys during April in Moree, Northern Slopes, Walgett and Narrabri RLPB districts identified Isolated–Scattered density adult locusts.
- There were patchy light rains (<20 mm) in all RLPB areas during 16-22 April and again during 23-30 April. Vegetation conditions are now mostly dry.
Forecast
- Fledging of nymphs was complete by late February in Moree and Walgett districts, and the decline in adult densities by early March where there had been swarms indicates migration of young adults. Wind directions at the end of February were to the south, but were predominantly to the west and southwest during March and April.
- The decline in adult population in March and in vegetation conditions during April would indicate that there is unlikely to have been significant breeding during autumn. However, localised low density egg laying by residual adults may have occurred, in Walgett or Moree RLPB districts. Eggs laid during March could result in a partial hatching during April, with a proportion entering diapause, while nearly all eggs laid in April would enter diapause, which will begin hatching in August, with a gradual emergence during August and September.
Risk(s)
- There is a low risk that some low density egg laying by residual adults occurred during April. Low and locally medium density nymphs are possible in some areas of this region during spring.
Far West
Bourke, Brewarrina, Cobar, Milparinka, Wanaaring & Wilcannia RLPB
Locusts and conditions
- Localised breeding occurred in the White Cliffs–Wilcannia–Milparinka area following immigration and heavy rains in January and in early February. The subsequent nymphal population fledged in mid-March leading to an overall increase in the adult population in Wilcannia and Wanaaring RLPBs. In early April high density adults were identified in the Wilcannia–White Cliffs area, with generally low densities elsewhere in the region.
- Surveys were conducted in Milparinka, Wanaaring, Wilcannia, Bourke and Brewarrina RLPB areas in early April. Concentration density adults were found in several locations between Wilcannia and White Cliffs and along the Paroo River, in low-lying areas of green vegetation following rains in February, and further rains in mid-March. Samples of females had developed eggs. Elsewhere in Wanaaring and Wilcannia RLPBs there were consistent Scattered and some Numerous density adults. Survey through Bourke and Brewarrina RLPB areas mid-April detected only occasional Isolated–Scattered density adults.
- There was light rainfall (<20 mm) in Wilcannia and Cobar RLPB districts in the last week of April. Vegetation is dry in most areas of the region, but there was some green areas east of White Cliffs in April.
Forecast
-
The high density adults in the White Cliffs–Wilcannia area in early April are likely to be the result of redistribution of locally fledged young adults to suitable habitats where rains fell in mid-March.
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The light trap catches at White Cliffs in March followed moderate rains during 22-23 March and probably reflect the migratory activity of young adults in the region. There were no catches during April, suggesting a cessation of nocturnal migratory activity. Winds were predominantly to the west during March and April.
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Rains in the White-Cliffs area during March and flooding from the Paroo River provided locally favourable conditions for breeding in April. High density egg laying is likely to have occurred in some locations in the area north of Wilcannia and east of White Cliffs, and along the Paroo River. A proportion of any eggs laid in late March may have hatched in late April, but most eggs laid in April would enter diapause and begin hatching from late August.
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Despite suitable habitat conditions in Bourke, Brewarrina and Cobar RLPB areas during March, there appears to have been little significant breeding in these districts, as adult densities remained low and no nymphs were found on survey.
Risk(s)
- It is likely that breeding has occurred in Wilcannia and Wanaaring RLPB districts, where there was green vegetation in April. Most eggs laid in April will enter diapause and hatch in early spring. There is a moderate risk from some bands during September and October, particularly in drainage areas east of White Cliffs.
- There is a low risk that low density migration occurred from the Wanaaring and Milparinka RLPBs into South Australia, or Southwest NSW during April.
South West
Broken Hill, Hillston and Balranald-Wentworth RLPB
Locusts and conditions
- There was an increase in locust population in Hillston and Broken Hill RLPB districts during March, with one area of medium–high density young adults developing between Menindee and Ivanhoe in early April. Adult numbers had declined to low levels in these districts by early May.
- Surveys were carried out in all RLPB districts in April, with Scattered–Numerous density adults recorded in some locations between Broken Hill and Ivanhoe, and south to Balranald. There were several counts of Numerous–Concentration density young adults, with occasional fifth instar nymphs in the Sayers Lake–Darnick area in early April. Occasional Isolated density adults were found in most of the Balranald-Wentworth RLPB district, with up to Numerous density near Pooncarie and Mildura.
- Surveys in early May through Hillston and Broken Hill RLPB areas identified only Isolated–Scattered density adults.
- Fowlers Gap light trap caught no locusts during April.
- There were light rains (<20 mm) in Hillston and Balranald-Wentworth RLPBs in late April.
Forecast
- The young adults in the Sayers Lake area in early April resulted from egg laying in the first week of February, associated with rain during 4-6 February.
- The moderate rainfall in March in Broken Hill and Hillston RLPBs provided green conditions for fledging nymphs to accumulate fat and may have initiated some autumn breeding. However, vegetation had dried off by early May and adults may have migrated from this area. Any eggs laid during April will enter diapause and hatch in late September.
Risk(s)
- There is a low risk that some low–medium density egg laying occurred during April in the areas of Broken Hill and Hillston districts that received rainfall during March, which could produce medium density nymphs in spring.
All locust activity should be reported to your Rural Lands Protection Board or NSW Department of Primary Industries.
A toll free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls.
QUEENSLAND
Southwest
Barcoo, Bulloo, Quilpie & Diamantina Shire
Locusts and conditions
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A few small Bands developed in early March in southern Barcoo and western Bulloo Shires, following immigration and localised breeding of adults in early February. Aerial survey in mid-March, however, did not detect any Bands in the areas where nymphs or high density adults were found by ground surveys. Nymphs fledged in March, but by mid-April adult numbers had declined to low densities throughout the region.
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Surveys were conducted in all Shires during April. There were Isolated–Scattered density adults in Bulloo and Quilpie Shires, with up to Numerous density near ‘Nappa-Merrie’, where there were nymphs in March. Young adults may have redistributed within the region or migrated during April as vegetation conditions dried out during April. Upper-level winds during the second half of March and April were predominantly to the west and northwest. Only occasional Isolated density adults were found in Diamantina and Barcoo Shires.
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The light traps at ‘Nooyeah Downs’ and at Birdsville recorded no locusts during April.
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There was no significant rainfall in this region during April and vegetation is dry.
Forecast
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The decline in the adult population may be the result of dry habitat conditions or migration during April.
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There may have been sporadic low density breeding in eastern Bulloo or Quilpie Shire following rains in mid-March. Some nymphs may have emerged during April, while remaining eggs will have entered diapause and will not hatch until August.
Risk(s)
- There is a low risk from sporadic breeding by remaining adults in March or April, which could result in medium density nymphs in some locations in August–September.
Locust activity should be reported to Biosecurity Queensland (QDPI&F). 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
Aramac, Barcaldine, Blackall, Boulia, Cloncurry, Flinders, Hughenden, Ilfracombe, Isisford, Longreach, Mckinlay, Mt Isa, Richmond, Tambo & Winton Shire
Locusts and conditions
- The locust population in areas surveyed declined to very low levels during March and April, with only occasional Isolated density adults and no nymphs found on surveys.
- Surveys were conducted in Longreach, Ilfracombe, Isisford, Barcaldine, Blackall and Tambo Shires of the Central West in mid-April. Only occasional Isolated density adult locusts were found in these shires, with more consistent Scattered density counts in Tambo Shire.
- Reports of locusts from several shires during March and April were identified as a mixture of other grasshopper species. Spur-throated locusts are widespread throughout this region.
- The Longreach and Julia Creek light traps recorded no significant plague locust activity during April.
- The was no significant rainfall in these regions during April and vegetation is dry.
Forecast
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Surveys indicate a decline to a very low population level in this region, while various species of grasshoppers, and spur-throated locusts were present at medium-high densities. There is likely to be only sporadic very low density breeding during autumn in these regions, which may produce occasional nymphs during winter or in August.
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No surveys were conducted in the Northwest region during April, but the population level is likely to have remained very low, and conditions are unsuitable for significant locust breeding.
Risk(s)
-
No specific risks are identified for this region during the forecast period.
Central Highlands
Bauhinia, Belyando, Emerald, Jericho & Peak Downs ShireLocusts and conditions
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No surveys were conducted in this region during April. Surveys in early March detected a very low density adult population.
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Reports of locusts in the Emerald and Bauhinia Shires in March and April were identified as predominantly spur-throated and migratory locusts by Biosecurity Qld staff.
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There were light rains (<20 mm) in parts of this region during the last week of April.
Forecast
- Vegetation and soil conditions remain favourable in some areas for possible low density breeding of the residual adult population, but there is a low probability of any significant breeding or population increase in this region at this stage in the season.
Risk(s)
- No specific risks are identified from this species during the forecast period.
South Central Queensland and Darling Downs
Balonne, Booringa, Bendemeer, Chinchilla, Inglewood, Milmerran, Murilla, Murweh, Paroo, Tara, Taroom, Waggamba, Wambo & Warroo ShireLocusts and conditions
- Locust population density remained very low in all areas of these regions except parts of Paroo Shire during April. Low density adults and occasional low density nymphs were detected in the Cunnamulla area of Paroo Shire in mid-April.
- Surveys were conducted in all shires of South Central Qld and in Murilla, Tara and Waggamba Shires of the Darling Downs during April. Occasional Isolated density adults were found in most areas, but consistent Isolated–Scattered density adults were only identified in the Wyandra–Cunnamulla area, along with Present density third instar nymphs between Thargomindah and Eulo.
- There were light rains (<20 mm) in Murilla, Tara and Waggamba Shires during the last two weeks of April. Rainfall in these regions was well below average during March and April, and pasture vegetation is dry in most areas. Some green vegetation persists along drainage lines in the Paroo Shire following flooding in February.
Forecast
- The consistent low density population in Paroo Shire reflects better habitat conditions in that area, both from heavy flooding during summer and moderate rainfall in mid-March and nymphs indicate some low density breeding in March. Those nymphs will have fledged at the end of April, but may represent a split cohort of developing and diapause eggs. Any diapause eggs will hatch gradually after winter and may produce medium density adults in some locations in spring. Further localised low density breeding could occur in parts of Paroo Shire in April and May.
Risk(s)
- There is a low risk from further localised breeding by residual adults in the Paroo Shire.
Locust activity should be reported to Biosecurity Queensland (QDPI&F). A toll free call to the APLC can be made on 1800 635 962. An answering machine is attached for after-hours calls.
VICTORIA
Locusts and conditions
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The extent of the adult population continued to increase in North Central Victoria during April and egg laying is likely to have occurred in some locations. Surveys indicate a widespread medium density population with most sampled females having developed eggs during April.
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In late March there were confirmed reports of adults at Stanhope, Waaia and Tatura in the area between Echuca and Wodonga in North Central Victoria.
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Surveys by DPI-Victoria staff in April identified a widespread Scattered–Numerous density population in North Central Victoria, primarily in the area bounded by Wodonga, Wangarratta, Rushworth, Echuca and the Murray River. There were also a number of reports from areas west of Echuca to Kerang in late April, and one confirmed report of egg laying in the Nhill area of southwest Victoria. Higher densities of locusts are mostly confined to dense grasses along roadsides, but Numerous density adults were also found on pastures and irrigated areas.
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APLC surveys in early May identified mostly Isolated and some Scattered density adults in Northwest Victoria west of Echuca. In North Central Victoria there were consistent Numerous density adults, up to Concentration in some locations, in the Rutherglen–Peechelba–Tungamah–Katamatite area. Occasional Present density second and third instar nymphs also indicate that some breeding occurred in this area after mid-March.
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There were light rains (<20 mm) in North Central and Northwest Victoria during the last week of April.
Forecast
- The increase in adult population in North Central Victoria is most likely the result of migration from adjacent areas of the eastern Riverina in NSW during late March and April. However, low numbers of adults may have migrated into Victoria from early January, when numbers began to increase in the Riverina. Occasional late instar nymphs reported in late March indicates some local breeding in early February.
- Locusts in areas west of Echuca may have moved into Victoria from the area south of Deniliquin in the Riverina during April.
- Breeding and medium density egg laying has occurred in some locations, particularly between Echuca and Wodonga. The low density mid-instar nymphs indicate some egg laying in March and may represent a partial hatching, with the majority of eggs now in diapause. Nymphs will remain in diapause at third instar over winter, but few are likely to survive to spring. Further sporadic egg laying will have occurred during April and may continue in early May.
- Hatching of eggs in North Central Victoria will begin in mid-October, and continue into early November. Peak hatching is expected from 20 October, assuming average temperatures. Nymphs in spring will fledge from late November into December. Breeding of that generation could potentially begin in late December or January if habitat conditions are favourable.
Risk(s)
- There is a moderate risk from localised areas of medium density nymphs during November, with some Band formation in North Central Victoria – particularly in the area between Wodonga and Echuca.
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
Far North, Northwest, Northeast Agricultural & Western Agricultural
Locusts and conditions
- Locust population density remained very low throughout northern South Australia during March and April, with the exception of the Innamincka–‘Cordillo Downs’ area in the far north of the Northeast region, where sporadic breeding by immigrant adults in early February produced a subsequent generation of adults in late March. Adult numbers had declined to low densities in this area by mid-April. There were no reports of locusts from other regions of South Australia.
- Ground surveys were conducted in the Innamincka–Cordillo Downs area of the Far North region in early March, where several areas of Numerous and Sub-band density mid-instar nymphs, and one small Band, were found close to Innamincka. Adult densities were Isolated–Scattered in this area, but very few adults were found in areas south of Innamincka. Aerial survey in the Cordillo Downs area in the Far North on 14 March did not detect any Band density nymphs. Further surveys in mid-April identified only occasional Isolated density adults in these areas.
- The Dulkaninna light trap recorded no locust activity during March and April.
- There was light rainfall (<20 mm) in the Western Agricultural region during 16–22 April and further light rains during the last week of the month. in that region, and in the southern Flinders Ranges area of the Northern Agricultural region. Vegetation conditions are dry throughout most of the state.
Forecast
- The decline in adult densities in the Innamincka area may have resulted from poor habitat conditions or migration during late-March and April.
- No significant autumn breeding is likely to have occurred in South Australia.
Risk(s)
- No specific risks are identified for South Australia 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.
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.
|
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 |
Rural Lands Protection Board (RLPB) or NSW Department of Primary Industries |
|
Queensland |
Department of Primary Industries & Fisheries (DPI&F) |
|
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
Australian Plague Locust Commission website
General regions referred to in the Bulletin
Location of APLC light traps (black circles).
Locust habitat areas shaded.
