LOCUST population density remained low throughout western Queensland, New South Wales, and in northern Victoria during January.
A localised infestation of nymphs has developed in the Burra–Gladstone–Peterborough area of the Northeast region of South Australia and there were a number of reports of nymph activity and hopper bands in that area during the second half of January.
There were few reports of locust activity in Victoria or Southeast South Australia, suggesting a continued population decline.
Surveys indicate continued low background population levels in the Far West, Far Northwest, Central West and Riverina regions of New South Wales, and in Southwest, South Central and Central West Queensland.
The outlook is for an increase in adult densities in the infested part of Northeast South Australia, following the fledging of the summer generation of nymphs during February.
Localised formation of a number of swarms is likely during the second half of February and this could result in some migratory redistribution within South Australia and the possibility of localised swarm egg laying.
The development of small, higher density populations is still possible during late summer in parts of Southwest Queensland, Far West New South Wales or the Far North of South Australia. However, there is a low probability that this would present a migration risk to agricultural areas during autumn.
The population level is expected to remain low in other regions of New South Wales and Victoria.
In South Australia, adult numbers declined in the Burra–Peterborough area during January, where there had been swarms during December, but there is now a generation of nymphs, following swarm egg laying in the area during the second half of December.
Hatchings commenced in the second week of January and bands of mid-instar nymphs were reported from near Georgetown, Spalding, Gulnare, Yatina and Narridy during the second half of January.
Nymphs will fledge from early to mid-February and localised swarm egg laying could follow in parts of the region in late February or March. The background population in the Northwest and Far North regions remained generally low during January.
Surveys in New South Wales showed a continuing low density population in all regions during January. Adult numbers remained very low in the Central West, Northwest, Darling and Riverina Livestock Health and Pest Authority (LHPA) areas.
There has been a small increase in population level over previous months in the Broken Hill–Wentworth–Balranald area of Western LHPA and occasional low density nymphs were identified in some locations in early January.
A further increase in population is likely in parts of the Western LHPA area, which could result in sporadic higher density autumn egg laying. Localised medium density populations could develop in other LHPA areas in late summer, which could produce small autumn nymphal populations, although if this occurs it is unlikely to present a widespread threat to agriculture.
Surveys in Southwest, South Central and Central West Queensland identified a continued low density adult population. Despite further heavy rainfall in parts of these regions during January, there is unlikely to be a widespread population increase, since two generations are generally necessary to produce swarms from low density populations.
The absence of any areas of higher density adults in Victoria is an indication of the continuing decline in population level. There is a low risk of any significant population development during February or autumn.
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