Currently in the Yass and surrounding districts there are localised low density populations of wingless grasshoppers. There is also the potential for other species namely the yellow winged locust to co-inhabit this area at the same time. They are mostly confined to areas with any green vegetation remaining after the excellent spring.
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The hatching of the wingless grasshoppers occurred towards the end of November, which is the normal time give or take a couple of weeks. The wingless grasshopper has five different growth stages called instars. Generally it takes approximately seven weeks to develop from the first instar to the adult stage. There is the potential given ideal conditions for them to remain in the area until late March or April.
Throughout December to late March, the adults may lay eggs in bare earth on north facing ridges. This can result in a significant increase in populations and the autumn break may create favourable conditions for breeding ensuring carryover for the next season.
The wingless grasshopper is a severe pest of improved pasture, preferably feeding on the legume component. Depending on density, it has been estimated that in low summer rainfall areas that a density of 30/m2 consumes 2.6 DSE/ha. During outbreaks, a lack of pasture may result in feeding on trees and home gardens.
Large control programs, such as those carried out for the Australian Plague Locust, are not undertaken with respect to the wingless grasshopper as outbreaks are generally localised. Control is at the discretion of the landholder. As green feed availability wanes so does the reproductive capability of the grasshopper, hence control is often not warranted.
Some insecticides are registered to control wingless grasshoppers; remember to follow the instructions on the label. Beware of the potential risks to non target species especially birds that include the grasshopper in their diet.
There has been research conducted for alternatives to chemical insecticides with the most promising bioinsecticide the fungus metarhizium trialled against the wingless grasshopper in Australia.