Current locust situation

The overall locust population increased substantially during autumn from previously low-level background to medium-high levels across much of the southern half of inland eastern Australia. Surveys conducted in late March only identified low-density populations in accessible parts of New South Wales and southern Queensland. However, surveys undertaken from mid-April onwards identified consistent medium–high density adults over much of New South Wales, north-western Victoria and South Australia with some low–medium density nymphs detected. Most sampled adult were observed with eggs developing or signs of egg-laying occurred. Only low-density adults were identified in inland Queensland except for the southern part of Channel Country where frequent medium-densities were identified. No locust captures were recorded by any light traps in Dulkaninna of South Australia, Fowlers Gap and White Cliffs of NSW until mid-February when 300 and 350 locusts were recorded by the light trap in White Cliffs on the two consecutive nights of 19–21 February, which indicates there was some successful breeding and movement after 25–50 mm of rainfall in the arid inland in late December. Several high captures were recorded in White Cliffs between early March and mid-April. The light trap in Dulkaninna did not catch any locusts during the whole season though the increase of nymphs and adults were observed locally since mid-February. The light trap in Fowlers Gap ceased operation after it was damaged by the heavy rainfall in early March while the one in Thargomindah of Queensland was not in operation during the season due to lack of operator. The UNSW insect monitoring radar in Hay detected some nights of significant locust migrations during late March to late April. A couple of dozen reports of locust swarming activities from inland NSW had been confirmed by the Local Land Services between mid-April and mid-May. The Department of Primary Industries and Regions South Australia (PIRSA) received appearance reports of locust swarms from the Flinders to Murraylands districts in late April. PRISA conducted ground surveys in mid-May and identified low-medium density adults remained in the Flinders district with test-drilling holes appeared on the ground (which indicates female adults tested the soil suitability for egg-laying and indicates these female adults were ready to lay eggs). Agriculture Victoria joining forces with APLC conducted ground surveys in the Mallee district in mid-May and identified consistent medium-high density adults. This season demonstrated that the locust population can rapidly build up from very low background to outbreak level under optimal conditions.

Heavy rainfall in February and March produced favourable habitats for locust breeding in inland eastern Australia and warm late autumn weather encouraged southward/south-eastward migrations and redistributions. Apart from some moderate rainfall in mid-September and mid-December respectively, the arid/semi-arid interior experienced a generally dry spring and early summer but received very much above average to highest on record rainfall in February and March with two-month totals of 100 – 400 mm with the heavier falls in the arid interior. Although the interior received little rainfall in April, above average to very much above average rainfall of 25 – 100 mm in May prolonged good habitat conditions for locust breeding. Autumn temperatures were above average to very much above average (0-3 degrees) except for the heavy March rainfall zone of South Australia at below average levels (0-2 degrees). Despite the forecast for below average rainfall and warmer temperatures for winter and likely El Niño development by the Bureau of Meterology, overwintering eggs are likely to survive with sufficient soil moisture. 
The overall outlook is for some medium-high density nymphs hatching in the southern part of inland eastern Australia with likely bands developing from mid-September onwards.

There is a moderate-high likelihood of a widespread infestation developing in spring.

The overall population remained at low-medium levels in autumn across inland eastern Australia with a significant buildup in Central West district of Queensland. Late instar nymphs were still observed by survey in early May, indicating an extended breeding season from November. Consistent Numerous to Concentration-density adults were identified by survey in Central West district with a Low-Density Swarm detected. Frequent Scattered to Numerous-density adults were also identified by survey in North West and Channel Country districts of Qld, North East district of South Austtralia and Upper Western district of New South Wales. Only a few captures were recorded by the light trap in White Cliffs in early April, but several reports of locust swarming activities were received from Central West Qld at the end of May. Although below average rainfall and warmer temperatures for winter were forecasted, habitat conditions should remain in favour for locust survival, and additional swarms are likely to form in winter.

There is a moderate risk of a regional infestation in Central West Queensland. However, a widespread infestation is less likely to occur in winter and spring.

The locust population persisted at a low – medium level in Central West district of Queensland in autumn, while the population declined significantly in the adjacent Central Highlands district. Locust bands were first reported +from the Central Highlands and confirmed by survey. Queensland Department of Primary Industries (QDPI) conducted several aerial controls of nymphal bands over a total area of approximately 16,000 hectares including organic properties in parts of western Central Highlands and eastern Central West during summer. Landholders also controlled some locust bands. QDPI has been closely monitoring the locust situation and controlled some small residual bands in mid-May in the northeast of Jericho (eastern Central West district). Surveys conducted in autumn identified Isolated to Scattered-density adults remained in the Central Highlands and similar levels of populations detected in the northern part of Channel Country with Scattered to Numerous-density adults identified in the Longreach-Hughenden areas. With the forecast for warm winter temperatures, habitat conditions should remain in favour for locust survival, and some breeding can occur where rainfall above 30 mm. Under low night temperatures of late autumn and winter, nocturnal long-range migration is unlikely but daytime short-distance dispersal can take adults tens of kilometres away in a warm day on a general westward direction.

There is a low-moderate risk of a regional infestation developing in the Central West and a low risk in the Central Highlands during winter and spring.