Locust situation 07 November 2023
This page summarises the known distribution of locusts during October 2023 and provides a brief outlook to January 2024. Regional information and forecasts are given in the latest Locust Bulletin.
Locust populations were at very low levels across inland eastern Australia, especially over the southern part of winter rainfall region, after a very dry late winter and early spring. The Channel Country in the arid inland, on the other hand, had slightly higher locust numbers. Surveys in the Channel Country identified occasional Scattered-density adults with frequent Isolated-density adults. Sporadic Isolated-density adults were identified in other parts of Queensland, New South Wales, and South Australia. Very few Present-density nymphs were detected by survey. No obvious populations of spring generation locust were detected in the southern part of inland eastern Australia. No hatching reports were received, nor any light-trap catches or radar detected flights.
Monthly rainfall totals were all less than 25 mm over the inland eastern Australia in the past three months, with especially low totals (less than 10 mm) recorded in September. After some heavy rainfall in the southern part of inland eastern Australia in June and in the northern part in early July, rainfall levels for the interior of eastern Australia ranged from average in some parts to below average to the lowest on record over all other parts for the past three months. Winter temperatures over inland eastern Australia were 1–3 degrees above averages, ranging at very much above average to the highest on record levels. The September temperatures continued this trend and were approximately 1–4 degrees above averages, ranging at above average to very much above average levels. October temperatures overall varied from below averages to 2 degrees above averages, mainly due to lower minimum temperatures. Habitat conditions were generally unfavourable in this early spring for locust breeding after the 3-season La Niña event ended in last autumn. An El Niño pattern started to form from August and the El Niño event is likely to last to early autumn 2024. Thus, below average rainfall and warmer temperatures are expected for late spring and summer.
The outlook for the remainder of 2023 is for overall low-level populations over the inland eastern Australia, with possible localised population increases under favourable habitat conditions in inland Queensland. It is unlikely that any bands or swarms will develop until summer, nor are any significant migrations likely to occur.
There is a very low likelihood of widespread infestations developing between now and summer.
The overall population was at low levels in early spring. Surveys from late September to late October identified widespread Isolated–Scattered-density adults in Queensland and occasional Isolated-density adults in New South Wales and South Australia. No nymphs were detected by survey. No captures were recorded on the light traps at Dulkaninna (SA), White Cliffs (NSW) and Fowlers Gaps (NSW). Habitat conditions continue to degrade, and lower rainfall is forecast for the remainder of 2023. Earlier breeding is therefore unlikely.
There is a low risk of a widespread infestation. Though, some localised breeding is possible to occur in favourable habitats of tropical and sub-tropical Queensland during the remainder of 2023.
The overall population was likely to remain at very low levels in early spring. No locusts were detected in areas surveyed during late September and late October. The usual occurrence area of southeastern Queensland had very much below average to the lowest on record rainfall in the past three months. Thus, breeding is less likely to have been occurring in these areas.
Limited localised breeding is possible under favourable habitat conditions. However, high-density infestations are unlikely to result from the current low background population levels.
There is a very low risk of a widespread infestation developing during the remainder of 2023.