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Locust Bulletin April 2008
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Locust Bulletin April 2008 - table of contents
General locust situation
Australian plague locust situation
Australian plague locust map March 2008
Rainfall events March 2008
Terms and Abbreviations used in the Bulletin
Map of forecast regions used in the Bulletin
General situation in March and outlook to mid-May 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 are widespread in Murray, Wagga and the western part of Hume Rural Lands Protection Board (RLPB) districts. Egg laying began in some locations in late March. The outlook for autumn is for further egg laying in the eastern Riverina and an extension of high density populations further west in the Riverina and possibly into adjacent areas of Victoria. A significant infestation with numerous hopper bands is expected to develop in the Riverina in October and November.
Aerial survey in the eastern Riverina in the first week of April identified several small swarms and widespread lower density adults, but the potential target areas are insufficient to initiate APLC control. Close monitoring of the situation will continue and information on egg laying locations is important to determine the probable extent of high density nymphs during spring. Landholder identification and control of small bands on farmland will be critical to minimising the impact of locust nymphs on crops during October and November.
An overall population increase to medium densities occurred in the Far West and Southwest regions of New South Wales during March, following fledging of nymphs in the Wanaaring–Tibooburra area in mid-March and the Menindee–Ivanhoe area in late March. Locust numbers declined in the areas of the Northwest Plains and the Central West where high densities had developed in late February, but population increases were reported in Molong and southern Dubbo, Forbes and Condobolin RLPB districts during March. This indicates a general movement to the south and east and a concentration of adults in suitable habitats, although some nymphs were reported from the southern Central West in early March. Egg laying will occur in these districts during autumn, with medium–high density nymphs likely to develop in some locations from early October.
In the western part of Bulloo and Barcoo Shires in Southwest Queensland, and the Innamincka– ‘Cordillo Downs’ area of Far North South Australia, several small areas of medium–high density mid-instar nymphs developed in early March, but aerial survey during 14–15 March did not detect any bands in those areas. Those nymphs fledged from mid-March and may have contributed to a local increase in the adult population. The adult population declined to very low densities in other regions of Queensland and South Australia during March.
There were several reports of adult locusts in the area between Echuca and Wangaratta in North Central Victoria in late March. The increase is the result of migration from adjacent areas of the Riverina, but low numbers of adults could have migrated into this region from as early as January. There is potential for further migration into North Central and Northwest Victoria during autumn.
There is a widespread medium density adult population throughout Central West Queensland, with up to Concentration density immature adults in several shires. In early March there were late instar nymphs at Present and Numerous density in Ilfracombe and Blackall Shires, and also in Belyando Shire in the Central Highlands, but fledging will have been completed by the end of March. Late instar nymphs were also found in Walgett RLPB district on the Northwest Plains of NSW in early March, indicating some breeding occurred in NSW during summer. Scattered–Numerous density adults were found on survey in the Central Highlands in early March, but high density adults were reported from southwest of Springsure in Bauhinia Shire. There were Scattered–Numerous density adults in South Central Qld, with Isolated density in areas of Southwest Qld.
Longreach light trap recorded high numbers of locusts during 5–17 March, with a peak of over 800 on 8 March. The light trap at Julia Creek recorded over 50 locusts on 13 and 14 March. The activity at Longreach may reflect the increase in the local population of young adults. 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.
High densities and some small swarms of adults may develop in the northern part of Central West Queensland, which is usual for this time of year. Immature adults often redistribute during autumn and form loose overwintering swarms, which may feed in green vegetation areas and roost in trees.
At the beginning of 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. Landholders on ‘Milroy Downs’ carried out control of nymphs in a sorghum crop on 3 March. Fledging will have continued in late March and there may be a resultant increase local in the adult population in this area during April. There were further reports of high density nymphs from other properties in the area southwest of Springsure during March, but in one location was confirmed to be a mostly of spur-throated and migratory locusts. Moderate rainfall in areas north of Emerald in mid-March may provide suitable conditions for breeding. 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 the southern Central Highlands.
6 April 2008
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Australian plague locust situation
Distribution of Australian plague locusts: 1 March to 31 March 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 March to 31 March 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
- Following the fledging of the widespread nymphal population in the eastern Riverina in late February and early March, adult population densities increased throughout the Riverina, with high densities of adults in Murray, southern Narrandera, and the western parts of Wagga and Hume RLPB districts. Significant autumn breeding is occurring in the eastern Riverina and Bands are likely to develop in these areas during mid-October and November. Localised breeding is likely also in parts of Hay and Riverina RLPB areas.
- Surveys at the end of March in Hay, Riverina and Murray RLPB districts identified Scattered–Numerous density adults in most areas, with up to Concentration density adults near Booligal and Carathool in Hay RLPB, and consistent counts of Numerous density in Narrandera RLPB. Concentration density adults were found in several locations in Murray RLPB, particularly to the north and east of Jerilderie. There were 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.
- Aerial surveys in Murray RLPB at the start of April found widespread Concentration and some swarm density adults, but the potential targets were insufficient to initiate an APLC aerial control campaign.
- There were several reports of locust activity from the western parts of Wagga and Hume RLPB districts during late March. High density adults were reported in the Temora–Stockinbingal area of Wagga RLPB district and egg laying was observed near Temora on 28 March. There were also reports from The Rock, southwest of Wagga Wagga, and from around Walla Walla and Walbundrie in Hume RLPB district.
- There were light rains (<20 mm) in all districts, with some moderate falls in Wagga and Hume RLPB districts, during 19–26 March.
Forecast
- The population increase throughout Hay and Riverina RLPB districts indicates a redistribution of adults from the eastern Riverina during March. It is likley that migration from the Central West region in early March has contributed to the adult population in the eastern Riverina. Some immigration to the western Riverina could possibly have occurred on 23 March from the White Cliffs area.
- The widespread Numerous–Concentration density adults in Murray, Wagga and Hume RLPB districts are the result of aggregation of adults following the local fledging of widespread medium density nymphs in late February and early March. Those nymphs came from breeding throughout the eastern Riverina late January. Occasional late instar nymphs in March indicate further sporadic low density egg laying in February occurred in some locations. There has been a general drift of adults to the east and south during March, with densities and reports increasing in southern Murray, Wagga and Hume RLPB districts during the month.
- Samples of high density adults displayed various stages of egg development. Reports indicate egg laying occurred in some locations in late March, and layings will continue throughout April. The widespread medium density adult population indicates the likely scale of autumn egg laying in the eastern Riverina, particularly in Murray RLPB. This will result in widespread medium–high density nymphs and Bands developing in spring. All eggs laid in late March and April will enter diapause, with peak hatchings in mid-October in southern Narrandera and Murray RLPB, and in late October to the south of Wagga Wagga. Sporadic egg laying may occur in Hay RLPB district, where hatching will begin in late September.
- Adults may move to the west into Riverina RLPB and contribute to a high density autumn breeding population in that district. Further movements into North Central and Northwest Victoria are also possible during April.
Risk(s)
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There is a high risk that egg laying in the eastern Riverina during March and April will produce numerous Bands in Murray, Wagga, southern Narrandera and western Hume RLPB districts in spring. Peak hatchings will occur in these areas from mid-October, with nymphs fledging after mid-November. Some swarms could develop in these areas during 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.
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
- A few small swarms developed at locations in the north of Coonamble district and near Nyngan at the beginning of the month. Locust activity then declined in these areas during March, but there were subsequent reports of increased adult numbers in Dubbo, Molong and Forbes RLPB areas.
- Surveys in early March through Nyngan, Dubbo, Condobolin and Coonamble RLPB areas found consistent Scattered–Numerous density adults in many areas. There were occasional Present density fourth and fifth instar nymphs between Lake Cargelligo and Condobolin, and near Trundle in Forbes district.
- In early March several Concentrations and small swarms formed near Wingadee, where there had been bands during February. A Medium density swarm covering 4 km2 was also detected at ‘Whitewood’ east of Nyngan. This was a very localised population, as adult numbers in surrounding areas remained at Isolated– Scattered densities. RLPB staff carried out control of the swarm at ‘Whitewood’.
- There were several reports of increased locust activity, including some nymphs, in the Dubbo and Molong Boards during the first half of March, but by late March 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.
- There were moderate rains (20–40 mm) in Nyngan, Dubbo, Molong, Coonabarabran and Forbes RLPB districts during 19–26 March, with light falls in Condobolin district.
Forecast
- The reported increase in adult population in the Dubbo and Molong RLPB districts in early March is likely to have been 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 early February. There has been a general drift of adult locusts to the east and south during March, with adult numbers gradually increasing to Numerous–Concentration densities by the end of the month.
- No general population increase in Nyngan or Coonamble RLPB districts was detected after the swarm identified at ‘Whitewood’ in early March, and there were no further reports. The absence of the forecast increase may indicate that there was only sporadic summer breeding in the Central West, but there may have been further egg laying in those districts in February and March.
- Some egg laying may have occurred in Dubbo, Molong and Forbes RLPBs during March, and breeding may continue in April. Most eggs laid after mid-March would enter diapause, with hatching extending from late August through September.
Risk(s)
- There is a moderate risk that medium–high density autumn egg laying has occurred in a number of RLPB districts in the region and will continue during April. There is likely to be a significant nymphal population in some areas during spring. Particularly in the eastern districts of Forbes, Molong and Dubbo. Pasture vegetation has dried off in many areas, but adults will have been able to develop eggs during March and will lay in dry soil during autumn.
- 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 district in late February, surveys in early March indicated that adult numbers had declined to medium densities in these areas. Young adults are likely to have migrated from these locations around that time resulting in redistribution within the region, and migrations to adjacent regions to the west and south. Elsewhere in the region there was a low density adult population.
- Surveys in early March identified Scattered-Numerous density adults on ‘Wilgabar’, and between and Cumborah and Walgett, where there had been swarm density young adults in late February. Adults were at Scattered–Numerous density elsewhere in the Moree and Walgett districts, with Isolated–Scattered adults in Narrabri and Northern Slopes districts throughout March.
- There were reports of low density adults from Kelvin and Mullaley, near Gunnedah, in Tamworth RLPB in late March.
- There were light rains (<20 mm) in Walgett and Narrabri RLPB districts during 19–26 March.
Forecast
- The known distribution of bands during February and the few observations of lower density nymphs elsewhere in Moree and Walgett RLPB districts during February suggest only sporadic high density egg laying in this region by swarms in January. Many adults may therefore have continued to migrate to the south in January.
- 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.
- Vegetation and soil conditions remained favourable for locust breeding during March and it is possible that breeding took place in some locations in the region, particularly 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. Diapause eggs would 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 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 mid-January and in early February. The subsequent nymphal population produced localised Bands that fledged in mid-March.
- Surveys were conducted in Milparinka, Wanaaring, Wilcannia, Bourke, Cobar and Brewarrina RLPB areas in early March. Several small areas of late instar nymphs at up to Band density were found on ‘Baronna Downs’ in the Wanaaring RLPB and also small Bands of third instar nymphs near Mt Sturt, in Milparinka RLPB. However, no Bands were visible during aerial survey of these areas in mid-March. There were Present density mid–late instar nymphs recorded in several other locations in Wilcannia and Wanaaring RLPBs.
- Survey through Bourke and Cobar RLPBs in mid-March detected only occasional Isolated density adults, with more consistent Isolated-Scattered densities in Brewarrina RLPB.
- Nymphs identified at ‘Golden Plains’ south of Goodooga in Brewarrina RLPB during February had fledged by early March and adult numbers had declined to low levels.
- There was a report of late instar nymphs at ‘Owen Downs’ in the Wanaaring RLPB in late March.
- White Cliffs light trap recorded locusts on several nights during the second half of March, with peak catches of 60 on 25 and 26 March, following rain on 23 March.
- There was light rainfall (<20 mm) in Wanaaring, Milparinka, Wilcannia and northern Broken Hill RLPB districts during 19–26 March, with moderate and locally heavy falls (20->50mm) in Cobar, Bourke and Brewarrina RLPB districts.
Forecast
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The late instars and fledglings on ‘Baronna Downs’ in early March indicate breeding by immigrant adults following rain in late January. The younger nymphs near Tibooburra and in the eastern part of Wilcannia RLPB are likely to have resulted from laying after further storm rains in the first week of February. Fledging of nymphs in this area occurred during the first half of March and an overall increase in adult densities in the Wilcannia, Wanaaring and Milparinka RLPB districts is likely during the forecast period.
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The light trap catches at White Cliffs followed moderate rains during 22-23 March. They probably reflect the migratory activity of young adults which fledged in the region during March, but immigration from the east also appears to have continued during the month. This nocturnal adult activity could reflect migration from this region on the predominant easterly winds during March. However, a trough system on 23 March provided one opportunity for southward movement into Southwest NSW or the western Riverina.
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Light–moderate rains in the White-Cliffs area during 22-24 March may have provided locally favourable conditions for breeding in late March. A small proportion of any eggs laid in late March could hatch in late April, but all eggs laid in April would enter diapause and begin hatching from late August.
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Some small swarms may have developed in areas where high density nymphs fledged in March, such as at ‘Baronna Downs’ and other locations in Wanaaring and Wilcannia RLPBs. These may have redistributed in the region, leading to an increase in adult population levels, and some may have migrated into adjacent regions.
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Despite suitable habitat conditions in Bourke, Brewarrina and Cobar RLPB areas during January and February, 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)
- There is a risk that breeding will occur in the Wilcannia and Wanaaring RLPB areas following rainfall during 22–24 March. Most eggs laid in late March or April will enter diapause and hatch in early spring.
- There is a low risk that low density migration of adults from the Wanaaring and Milparinka RLPBs could increase population levels in South Australia, or Southwest NSW during April.
South West
Broken Hill, Hillston and Balranald-Wentworth RLPB
Locusts and conditions
- There was an overall increase in locust population to medium densities in areas surveyed by the end of March and one area of medium–high density young adults between Menindee and Ivanhoe in the east of Broken Hill RLPB district.
- Surveys were carried out in Broken Hill and Hillston RLPB districts at the end of March, with Scattered–Numerous density adults recorded in some locations in between Broken Hill and Ivanhoe, and south to Balranald. In the Sayers Lake–Darnick area several counts of Numerous–Concentration density young adults, with occasional fifth instar nymphs, were identified on 31 March. Small bands of nymphs had been reported from this area in mid-March, indicating adult egg laying after storm rainfall in this area in the first week of February.
- Fowlers Gap light trap caught low numbers of locusts on several nights during the first half of March.
- There were light–moderate rains (10–30 mm) around Broken Hill and Ivanhoe during 19–26 March, and light falls (<20 mm) in Balranald-Wentworth RLPB. There has been some green vegetation response in the Broken Hill–Ivanhoe area.
Forecast
- The Numerous–Concentration density adults in the Sayers Lake area have resulted from egg laying by adults in the first week of February, associated with rain during 4-6 February. There was an influx of adults into the Wilcannia–White Cliffs area of the Far West in late January, and some may have continued to migrate southwards into this region.
- The moderate rainfall during 22–24 March in Broken Hill and Hillston RLPBs provided green conditions for fledging nymphs to accumulate fat and may initiate some autumn breeding. The higher density young adults will not have developed eggs until mid-April, however, and vegetation may have dried off by that time. Any eggs laid during April will enter diapause and hatch during September. The outlook for spring is therefore a potential for some low–medium density nymphs in the Broken Hill and Hillston RLPB districts.
- Redistribution of young adults to other RLPB districts within the region, or some migration into South Australia, Northwest Victoria or western Riverina is possible during April. Migration from the high density population in the Riverina into the Balranald-Wentworth RLPB could also increase the autumn breeding population.
Risk(s)
- There is a risk that medium density egg laying will occur in the areas of Broken Hill and Hillston districts that received rainfall during March. Young adults from the Sayers Lake area could breed in these areas during April, or migrate in low numbers into South Australia or Northwest Victoria. Migration from the Riverina into Balranald-Wentworth RLPB is possible during April.
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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Following immigration and localised breeding of adults in early February, medium density nymphs, and a few small Bands developed in early March in southern Barcoo and western Bulloo Shires. 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. Adult densities were generally low in other areas of Bulloo and Quilpie Shires.
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Surveys were conducted in Bulloo, Barcoo and southern Diamantina Shires in early March, and in Quilpie Shire in mid-March. There were consistent Scattered density adults in Barcoo and Bulloo Shires, with up to Numerous density near Noccundra. In the ‘Nappa-Merrie’ and Lake Pure area on the western edge of Bulloo Shire, and around ‘Planet Downs’ in Barcoo Shire, there were widespread Present density mid-instar nymphs, with small areas of Sub-band density. By mid-March the nymphs at ‘Nappa Merrie’ were fledging and there were Numerous density young adults in some locations. Surveys throughout Quilpie Shire in mid-March identified Isolated and Scattered density adults north of Quilpie.
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The light traps at ‘Nooyeah Downs’ and at Birdsville recorded no locusts during March.
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There was light-moderate rainfall (10-30 mm) in Quilpe and the eastern part of Barcoo Shires during 19–26 March.
Forecast
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Surveys in early March showed a decline in adult numbers in the areas where Concentration and swarm densities had been found in early February. The small increase in numbers elsewhere in this region could have resulted from redistribution after that time, but adults may also have moved to the west with the prevailing winds.
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The ages of most nymphs near ‘Nappa Merrie’ in early March, indicate egg laying in early February, probably immediately after rains on 5 February. These nymphs fledged in mid-March, which will result in a local increase in population in the western part of this region. Young adults may also have migrated from that area, as vegetation conditions have continued to dry out during March. Upper-level winds during the second half of March were predominantly to the west and northwest.
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Low density breeding is possible in low lying areas where green vegetation remains in western Bulloo Shire during April, which would produce nymphs during August and September,
Risk(s)
- There is a low risk of sporadic breeding by remaining adults in April. If this occurs in association with further rains, it 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, with only occasional Present density adults and no nymphs found on surveys.
- Surveys were conducted in Ilfracombe, Isisford, Blackall and Tambo Shires of the Central West in late March. Only occasional Isolated density adult locusts were found in Blackall and Isisford Shires.
- A report of locusts from Tambo Shire in mid-March was 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 March.
- The only significant rainfall in these regions during March was isolated falls in Cloncurry Shire during 19–26 March and light–moderate rain in Aramac and Flinders Shires in the last week of the month.
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 are present at medium-high densities. There is likely to be only sporadic very low density breeding during autumn in this region, which may produce occasional nymphs during winter or in August.
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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Surveys were conducted in all shires of this region in late February and early March. A low density adult population was recorded.
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Reports of locusts southwest of Springsure in Bauhinia Shire, were identified as predominantly spur-throated locusts.
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There were light rains (<20 mm) in southern Bauhinia Shire during 19–26 March, and moderate falls (20–40 mm) in Emerald, Peak Downs and Belyando Shires.
Forecast
- Vegetation and soil conditions remain favourable in many areas for possible low density breeding of the residual adult population, but there is a low probability of a 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
- Surveys were conducted in Balonne, Murweh, Booringa, Bungil, Waroo, Murilla, Tara and Chinchilla Shires during March. Population density in these shires was very low, with only occasional Isolated density adults found in Tara Shire. There were no reports of locusts activity.
- There was light rainfall (<20 mm) in Paroo and Balonne Shires during 19–26 March. Pasture vegetation has dried off in most Darling Downs Shires.
Forecast
- The decline to very low adult population densities suggests no significant locust breeding in these regions during late summer. It may also indicate continued general migration of adults to the southwest and west during March. The reduction in adult densities in the ‘Carinya’ area in Balonne Shire by the beginning of March did not result in an increase in densities in surrounding areas, which would support migration out of this region.
- It is possible that residual adults bred at low densities in part of Balonne or Paroo Shire during March, which could produce a split cohort of developing and diapause eggs during April. Adult densities may be higher in the Cunnamulla area in Paroo Shire, where vegetation and soil conditions remain suitable for breeding.
Risk(s)
- No specific risks are identified for this region during the forecast period.
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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There were several reports of adult locusts in part of North Central Victoria during the second half of March.
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There were confirmed reports of adults at Stanhope, Waaia and Tatura in the area between Echuca and Wangarratta in North Central Victoria at the end of March. Adult densities in the area are generally low, but there were Numerous and some small Concentration densities at some report locations. Sampled locusts showed no egg development.
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There were light–moderate rains (20–30 mm) in North Central Victoria during 19–26 March, with light falls in part of the Northwest region.
Forecast
- The increase in adult population in northern Victoria is most likely the result of migration from adjacent areas of the eastern Riverina in NSW during the second half of March. However, low numbers of adults may have migrated into Victoria from early January, when numbers began to increase in the Riverina, and the presence of occasional late instar nymphs indicates some local breeding in early February.
- Further immigration into North Central or Northwest Victoria, primarily from the Riverina, is likely during April.
- Some localised egg laying is likely during April. Eggs will enter diapause and most hatching will occur in late October.
Risk(s)
- There is a risk from localised areas of medium density nymphs, possibly with some small Bands, developing during November in North Central Victoria.
- There is a risk of further immigration into Victoria from the Riverina and medium–high density egg laying in some locations during April.
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 was very low throughout northern South Australia during February and is expected to have remained low during March, 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.
- 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.
- The Dulkaninna light trap recorded no locust activity during March.
- There was no significant rainfall in South Australia during March and vegetation conditions are dry throughout most of the state.
Forecast
- The decline in adult densities in the Innamincka area may indicate redistribution or some migration, following sporadic high density breeding in early February. The majority of nymphs in that area fledged in mid–March and a subsequent local increase in adult population is likely. Easterly winds were predominant during March, but some southward movement of young adults was possible on 23 March, associated with a low pressure trough.
Risk(s)
- There is a low risk that immigration of adults from Far West or Southwest NSW, or from Southwest Qld may bring some adults into the Northern Agricultural and Far North regions during April.
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.
