Locust Situation 8 January 2015
This page summarises the known distribution of locusts during December2014 and provides a brief outlook to March 2015.
The next Locust Bulletin will be produced in February 2015.
Australian Plague Locust (Chortoicetes terminifera)
Swarm egg laying was reported from South Central, Central West and Southwest Queensland, and in Central West and Far West New South Wales during the first half of December. The locations and timing of egg laying were sporadic and no areas of intense swarm egg laying have been identified. However, the few confirmed observations of laying are likely to reflect more widespread breeding events and lower density egg laying is also likely to have occurred. Adults continued to redistribute locally to aggregate in areas of favourable habitat conditions within these regions, as storm rainfall increased the geographic extent of favourable areas. Egg laying commenced at the start of December in Southwest Queensland and reports continued to 20 December in South Central Queensland and in Central West New South Wales. Hatching commenced in late December and is likely to have peaked at the start January. Nymph bands were reported from several locations in these regions in late December. Landholders are requested to report hatching to state agriculture agencies or the APLC.
There was a decline in adult numbers in Far West and parts of Central West New South Wales in December as a result of migration and natural mortality. Swarms reformed to lay eggs in the Bourke–Louth and Gilgandra–Coonamble areas in early December. There was a small increase in adult numbers in the Walgett and Narrabri districts of the Northwest Plains region and localised swarm egg laying was reported in the Burren Junction–Pilliga area in mid-December. Early instar bands were reported from numerous locations in the Gilgandra-Coonamble area at the start of January.
In Southwest Queensland localised swarm activity and egg laying was observed near Betoota–Planet Downs, Durham Downs–Mt Howitt and Nockatunga in early December. Swarm egg laying was reported from the Charleville–Augathella and the Injune–Roma–Mitchell areas of the South Central region from 9 December. Swarms moved into the Miles–Condamine, St George–Thallon and Goondiwindi–Moonie areas in mid-December and swarm egg laying occurred in areas of recent rainfall. December rainfall produced favourable habitat conditions for egg laying and nymph survival throughout the South Central, Central West and Central Highlands regions. Hatching reports at the start of January indicate the highest intensity of band development will be in the Roma–Mitchell–Injune area.
Locust densities remained generally low in South Australia. Localised storm rainfall in part of the Far North and Northwest regions during December may have initiated some egg laying, but nymph survival will be limited in the absence of further rainfall.
Locust densities remained low in Victoria during December. Occasional mid-instar nymphs were identified by Department of Environment and Primary Industries staff near Echuca in early December.
The January outlook is for a significant nymphal generation with many bands in South Central Queensland. More localised hopper bands will develop in Central West Queensland and Central West New South Wales. Habitat conditions are suitable for nymph development and survival in these regions. Localised high density nymphs could also develop in parts of Southwest Queensland and Far West New South Wales, but nymphal survival may be limited by drying conditions. Fledging of summer generation nymphs will commence in late January and continue in early February. Swarm formation is likely in these regions during February with a widespread infestation possible in South Central Queensland. The risk of migrations to other regions will increase in February.
Spur–throated Locust (Austracris guttulosa)
There is a low density adult population throughout inland Queensland. Surveys during November and December identified Isolated–Scattered density adults in the Central West, Northwest, Southwest, South Central and Central Highlands regions of Queensland. Occasional adults were identified in Far West New South Wales.
The current adult population is expected to have commenced breeding in regions where there was heavy rainfall in late November and early December. The heavy rainfall in the Queensland Central Highlands, Central West, South Central and Gulf regions will initiate egg laying and low density nymphs are expected to appear during January and February. Adults can lay multiple egg pods during the summer wet season, so the distribution of further rainfall during January–March will influence the duration and success of the breeding cycle. The current low adult population level indicates that breeding is likely to produce a moderate overall population increase in 2015.
Migratory Locust (Locusta migratoria)
Surveys during November and December indicated a moderate increase in population level in the Central Highlands and parts of Central West and South Central Queensland. Scattered density adults were identified in the Springsure–Wharton Creek–Rolleston and Arcadia Valley areas, with Numerous density recorded at some locations. Low density nymphs were detected at one location. Low density adults were also recorded in the Mitchell–Augathella and Clermont–Alpha areas. The widespread heavy rainfall during December will provide suitable conditions for further localised breeding. In late December, localised swarms developed in the Wharton Creek area, southwest of Springsure. Gregarious egg laying was observed by landholders on several properties, who reported early instar nymph bands in early January. Landholders are carrying out control of hopper bands. There is a moderate risk of further localised gregarious population developments and of a significant population increase in the southern Central Highlands during January and February.
Map of locust forecasting regions mentioned on this web page
Circles indicate locations of APLC light traps.
Shaded areas indicate potential locust habitat areas.