This page summarises the known distribution of locusts during January and provides a brief outlook to April 2019. Regional information and forecasts are given in the
latest locust bulletin.
The locust population level remains low over most inland regions in eastern Australia. Only limited surveys were conducted during January, because of the very low numbers identified in previous months and continued very dry habitat conditions in inland areas. Medium density young adults and nymphs were reported from several locations in the Hunter Valley and Central Tablelands regions of New South Wales during the second half of January. Population persistence in peripheral habitats when numbers are very low in the inland has also occurred during several previous widespread droughts. Several other species, notably the yellow-winged locust, have produced medium and locally high density populations in eastern districts of Queensland, New South Wales and Victoria.
Survey in the Riverina and Central West regions of New South Wales recorded only low density adult locusts in most areas. The localised population in the Lake Cargelligo district persisted during January, with medium density adults still in the same small area. Locust reports from the Hunter region extended from Muswellbrook to Murrurundi and from Bylong to Gulgong in the Central Tablelands.
No surveys were conducted in Queensland, but only occasional locusts were recorded in most areas in recent months. Heavy rainfall in the Northwest, Southwest, Central West and Gulf regions of Queensland at the end of January will produce widespread favourable habitat for locust breeding.
Previous surveys in South Australia recorded no locusts and habitat conditions remain very dry.
No surveys were conducted in Victoria, but locust numbers are expected to have remained low in inland habitats. The population persisting in the Omeo–Swifts Creek area in East Gippsland in January is mixed with several grasshopper species. Surveys by Agriculture Victoria indicate that locusts only make up a small proportion of the total numbers of flying insects.
The outlook for February and autumn is for population densities to remain generally low in inland eastern Australia, although small population increases are likely in New South Wales and Queensland. A moderate population increase is likely in eastern New South Wales, particularly in the Central Tablelands, Northwest Plains, and Central West regions. Further breeding is possible during February in the Central Tablelands and Hunter Valley and small swarms could develop in autumn. Low density migrations from these areas could increase adult population levels in the Central West and Northwest Plains regions. Heavy rainfall in Northwest, Central West and parts of Southwest Queensland will provide favourable habitat for widespread locust breeding. Nymphs are likely to develop in some areas from late February, but mostly at low densities. An increase in adult numbers to medium densities is likely in parts of these regions during autumn. The Bureau of Meteorology seasonal outlook for February to April 2019 indicates continued above average temperatures, which could increase locust mortality in dry regions. The rainfall outlook predicts average rainfall is likely in New South Wales and Queensland. Despite the low current population levels, successful breeding could therefore result in population increases in some regions during autumn. However, there is currently a low probability of high density populations developing in any inland region.
There is a low probability of widespread regional infestations developing during February or autumn.
The population level remained very low in areas surveyed during December and January. No surveys were conducted in Queensland during January and the species was not detected in New South Wales.
The heavy rainfall in the Northwest, Central West and Gulf regions of Queensland at the end of January will provide the first opportunity for widespread breeding for 2018-19. Adult females can produce several pods and egg laying is often initiated after rainfall. However, the very low adult population numbers in surveyed regions are unlikely to produce a large nymph population. Hatching is likely during March and nymphs would fledge in late April. Nymphs and eggs are susceptible to desiccation and high nymph mortality can occur if habitat conditions become dry.
There is a low risk of a widespread infestation developing during 2018-19.
No surveys were conducted in Queensland during January. This species has not been detected since October, when very low numbers were recorded in the southern Central Highlands region of Queensland. Rainfall in that region and parts of Central West and Northwest Queensland during January could initiate low density breeding that would contribute to maintaining an overall low population density.
There is a low risk of a widespread infestation developing during February or autumn.