Central Queensland grain growers are urged to be vigilant about monitoring crops for fall armyworm this winter growing season following the recent detection of the invasive moth pest as far south as Bundaberg.
Department of Agriculture and Fisheries (DAF) Principal Entomologist, Dr Melina Miles, says fall armyworm (Spodoptera frugiperda) was initially detected in the Gulf of Carpentaria in January and had now been found in the Northern Territory, Western Australia and as far south as the Wide Bay Burnett region of Queensland.
Armed for battle
Despite fall armyworm being considered a highly destructive pest overseas - known to feed on more than 350 plant species and causing significant economic losses - Dr Miles says the Australian grains industry is well positioned to respond effectively.
"In North America, autumn is a key time for fall armyworm to migrate," she says.
"Adults are highly mobile and quite capable of travelling large distances quickly.
"Their migration rate is remarkably fast, estimated at up to 500 kilometres during this period of migration.
"Whether we will see the same pattern of annual, long-distance migration from the tropics south remains to be seen.
"However, I believe the impact of this pest in winter or early sown spring crops will be limited by the cooling conditions in southerly regions, but I could be wrong."
In the paddock
Dr Miles says the key to effective management will be regular monitoring, and she is urging growers with cereal crops in the ground to be alert to the arrival of the pest.
"Fall armyworm has been devastating in overseas farming systems when it was not detected early and where options for control were unavailable," she says.
"But the Australian grains industry is already regularly monitoring and insecticide permits are now in place for the majority of grain crops for fall armyworm management."
Dr Miles says vigilance is the key from here and that means regularly checking for early signs of pest activity and crop damage - and importantly correctly identifying of fall armyworm caterpillars.
"Identification is an area in which growers and agronomists will need support, as there are already many native Spodoptera species in Australia, but there are some excellent resources to help," she says.
GRDC Manager Biosecurity, Jeevan Khurana says the GRDC is working closely with industry partners to characterise the pest, estimate potential impacts and develop management options, as well as identify and prioritise research, development and extension gaps.
"The GRDC has now collated information resources on fall armyworm, including an overview of emergency use permits on the GRDC website," Dr Khurana says.
To date in Australia infestations of the pest have been identified in sweet corn, maize and sorghum.
Dr Miles says, based on the overseas experience, local researchers are expecting fall armyworm to favour these crops.
"But it is also a broadleaf - as well as a grass - pest, so we will have to watch and check how it responds to Australian conditions," she says.
"At the moment, we believe much of the damage caused by this pest is likely to happen in the vegetative stage of crop development, which, depending on pest densities, may have minimal impact on final yield or quality.
"When determining what action to take, we need to keep this in mind - as well as recognise that fall armyworm has developed resistance to chemical controls in overseas countries and we need to minimise the risk of that happening here."
Dr Miles says accurate identification of the pest, as well as rational assessment of crop damage, will be critical in terms of determining when an insecticide is required.
She says collections of fall armyworm larvae from the Burdekin and Atherton regions had already shown the presence of fungal disease and a number of natural enemies parasitising the fall armyworm larvae.
Dr Miles says it is also highly likely that there will be predators and egg parasitoids attacking fall armyworm.
For information about identification go to business.qld.gov.au/fallarmyworm. To report a sighting in Queensland, call DAF on 13 25 23, or the Exotic Plant Pest Hotline 1800 084 881.
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