The fall armyworm is pushing ts way south in Western Australia and in a concerning trend for that state's agriculture sector samples have revealed some samples of the insect are resistant to popular insecticides. Fall armyworm has spread as far south in WA as Carnavon, after only being found in Australia in February in far north Queensland.
Samples of fall armyworm have been collected by the WA Department of Primary Industries and Regional Development (DPIRD). These samples involved fall armyworm larvae collected from parts of northern WA.
After screening by the NSW DPI it was found all of the larvae contained at least one of the mutations that passes on resistance to Group 1 insecticides, which includes both carbamate and organophosphate groups of products. DPIRD applied entomologist and fall armyworm project manager Helen Spafford said there were significant amounts of resistance.
"Half of the larvae from Kununurra and 60 per cent from Broome were homozygous resistant for the same mutation," Dr Spafford said. "While further testing is necessary, this demonstrates the presence of a gene for resistance in fall armyworm across two locations in the Kimberley region, and the potential for the mutations to be more widespread.”
According to an article on queenslandcountrylife.com.au¸ Dr Spafford urged farmers to carefully monitor their insecticide use, especially Group 1 products to limit the spread of resistance.