This page summarises the known distribution of locusts during March and provides a brief outlook to Spring 2019. Regional information and forecasts are given in the
latest locust bulletin.
The locust population level remained very low and in decline over most inland regions due to generally ongoing drought conditions in most of eastern Australia. A moderate population increase previously identified in the Central West and Northwest Plains of New South Wales appears to have declined. Locust numbers remained low in NSW, with almost no counts in Victoria and South Australia. Low numbers were also recorded from the Channel Country up to Central West Queensland. No nymphs were identified in any surveys in March and habitat conditions remained very dry. There were no evidence of any significant locust activities.
Surveys in parts of the Central West of New South Wales indicate that the previous medium-density adult locusts in the Coonamble district had declined. A suitable weather system in mid-March may have encouraged some short-distance emigrations from the Coonamble region. Survey of the Riverina and Far Southwest regions only found very low density of adult populations.
Survey in Northwest Victoria did not detect any individuals. Locust numbers are expected to have remained very low in inland habitats. The population in the Omeo Valley and Swifts Creek areas in East Gippsland are expected to have persisted.
Surveys conducted in South Australia detected only very low numbers in the northeast corner of the state. Some floodwaters entered from Queensland from mid-February but had so far only produced limited vegetation response along the affected drainage systems.
Surveys in Queensland identified occasional adults in the Southwest and Central West regions, but no nymphs were detected. Flooding in the Northwest generated some green vegetations downstream along the affected channels in the Southwest, where survey access was restricted, but large areas of the Southwest remained dry before the landfall of Cyclone Trevor. Despite the widespread heavy rain associated with the ex-cyclone in late March, locust numbers are expected to remain low due to the current low background population level. However the wet conditions and subtropical climate may stimulate some late breeding. The locust situation in Queensland will be closely monitored throughout autumn.
The outlook for the remainder of autumn is for continuing low population densities in most regions of inland eastern Australia. However, widespread heavy rainfall in Queensland in late March will produce favourable habitat conditions for locusts. Egg laying could occur during April and May, and an extra generation could therefore be produced in subtropical areas of Queensland. However, as the current population level is so low, there is only a low probability of any significant population increase in the short term, nor a high-density of nymphs in spring in inland regions where egg laying could take place.
There is a low probability of widespread regional infestations developing during autumn or spring.
The population level remains extremely low this season. Only two isolated adults were detected in Central West Queensland during surveys in March, but none were recorded in any other areas surveyed.
Heavy rainfall in the Northwest, Central West and Gulf regions of Queensland at the start of February may have provided some suitable habitats for breeding, but no adults or nymphs were detected in the Southwest where floodwaters generated green vegetation. Adult females can produce several pods and egg laying is often initiated by rainfall. However, the very low known adult population prior to the rains and late commencement of any breeding, indicate that a large autumn nymph population is very unlikely. With the additional widespread rainfall in late March, possible egg laying could occur in April and hatchings could commence during April with adult fledgings in late May to June. Locust habitat in the Central Highlands region was mostly dry but received some rainfall in the second half of March with the population level not expected to increase dramatically.
There is a low risk of a widespread infestation developing during 2019.
This species has not been detected since October 2018, when very low numbers were recorded in the southern Central Highlands region of Queensland. Rainfall in parts of Central West and Northwest Queensland in early February could have initiated some breeding that would contribute to maintaining overall very low population densities.
There is a low risk of a widespread infestation developing during autumn or spring.