Landholders in far East Gippsland are being urged to be on the lookout following reported sightings of locust activity in areas of the Tambo Valley north of Swifts Creek and as far south as Bruthen and Mossiface.
Thirty-three specimens were collected from different locations in the area and handed in to local Agriculture Victoria staff last week.
Agriculture Victoria Senior Entomologist and Victorian Plague Locust Commissioner Dr Kyla Finlay said that work is being done to positively confirm the identification of the specimens.
'An initial visual identification of the specimens from images suggest the majority may be Yellow winged locust and other native grasshopper species, with relatively few Australian plague locust.
'However, the Yellow winged locust can behave in a similar manner to Australian plague locust and form high density swarms and bands.
'We are conducting surveillance in the areas where reports have been made to monitor the extent of the occurrences.
'There have been positive identifications of Australian plague locusts in the area before, in 2010 and 2018, however, these occurrences are intermittent.'
There are more than 500 types of locusts and grasshoppers in Australia and of these, only four are regarded as economically important. Only two of these - the Australian plague locust (Chortoicetes terminifera) and the Yellow winged locust (Gastrimargus musicus) -regularly occur in Victoria.
Agriculture Victoria Industry Development Officer John Commins said if positively identified, the locusts could potentially impede the opportunity for farmers to cut hay and make silage.
'When present in large numbers, they can strip green crops, severely limiting the capacity of farmers to build up hay and silage reserves, and harvest summer fodder crops,' he said.
Mr Commins said farmers can potentially protect fodder crops by laying down a barrier spray around crops to stop young locusts in their tracks when they are banding and marching.
A number of insecticide products are available for the treatment of Australian Plague Locusts.
These products fall into four broad groups:
- biologicals
- organophosphate/carbamate compounds
- phenylpyraxole formulations
- synthetic pyrethroids.
Insecticide products suitable for controlling Australian plague locusts will work for Yellow winged locusts.
Landholders should seek expert advice from a chemical reseller or agronomist as to which insecticide best suits their situation and use the chemical products according to the label instructions. All chemicals must be used in accordance with Victorian legislation.
Dr Finlay said the most effective time to spray is when the hoppers are relatively small and are just starting to form aggregations or bands on the ground. For Australian plague locusts this is about two weeks after hatching when the hoppers are around 10mm long. Yellow winged locust hopper will take slightly longer to reach the aggregation stage and be slightly larger.
'By spraying and controlling them at this point in their development cycle, this will suppress any population build-up and reduce potentially high population levels next year,' she said.
Australian plague locust (Chortoicetes terminifera) can be identified by the large dark spot on the tip of the hindwing and the distinctive red shanks on the hind legs. Their body colour varies and can be grey, brown or green. Adult males are 25 - 30mm long while females are 30 - 45mm long.
The Yellow winged locust (Gastrimargus musicus) are larger than the Australian Plague Locust. Adult males are 25 - 35mm long and adult females 35 - 40mm long. They are easily distinguished by the bright yellow colour and brown banding on the hindwing.
There are a number of resources available on the Agriculture Victoria website with advice on how to identify locusts, recognise locust egg laying and swarming and insecticide use for managing locusts - visit our Australian Plague Locusts pages.
