REDLEGGED earth mites (RLEM) resistant to insecticides have been found in South Australia and authorities believe their spread eastward to Victoria and southern NSW is inevitable.
Paul Umina, entomologist with Cesar and The University of Melbourne, was not surprised the resistance, first observed in Western Australia over a decade ago, has now been found in other parts of Australia.
“You could say it was just a matter of time,” he said.
Tests have found multiple RLEM populations resistant to insecticides based on synthetic pyrethroids (SPs, such as bifenthrin and alpha-cypermethrin, and organophosphates (OPs), including omethoate and chlorpyrifos.
Dr Umina said in most cases SP resistance was more pronounced than OP resistance