Grain growers, particularly those in central and coastal Queensland, are urged to be vigilant about monitoring crops for fall armyworm following the detection of the invasive moth pest at different sites in northern Australia.
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 more recently found on the Atherton Tablelands and in the Burdekin region.
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.
Watch and act
Speaking at a recent GRDC Grains Research Update in Goondiwindi, Dr Miles said the industry's proven record of regular monitoring and well-educated agronomists and growers would prove integral to successful management of this pest.
Her Update presentation features on a new podcast about fall armyworm.
"Fall armyworm has been particularly devastating in overseas farming systems when it was not detected early and where options for early control were unavailable," Dr Miles says.
"But the Australian grains industry is already accustomed to regular monitoring, we also have very well-informed agronomists and growers, and insecticide permits are now in place for the majority of grain crops for fall armyworm management.
"Vigilance will be key from this point and that means regular checking for early signs of pest activity and crop damage and, importantly, the correct identification 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."
What's at risk
Dr Miles says while fall armyworm was a newcomer to Australia and its behavioural patterns and impact here would be the focus on new research, the invasive pest was expected to present a major risk for sweet corn, maize and potentially sorghum crops.
"Based on the overseas experience, we are expecting fall armyworm to favour these crops, but it is also a grass (as well as a broadleaf) 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 may have minimal impact on final yield or quality.
"When determining what action we 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.
"It will be critical that growers and agronomists accurately identify the pest, rationally assess damage and be conservative in what action they take, especially when it comes to broad spectrum insecticide use."
Dr Miles says it is highly probable there will be several natural predators to the fall armyworm eggs and larvae, such as parasitoid wasps and generalist predators.
Looking ahead, she says from here it will be a case of 'monitor and manage' for Queensland growers, particularly those in central and coastal areas.
"Fall armyworm is likely to establish in northern Queensland during the summer months and the length of the wet season will influence population build up," Dr Miles explains.
"If rain stops March/April, it will be a key time for fall armyworm to move in search of more food.
"Adults are highly mobile and quite capable of travelling large distances quickly. Their migration rate is remarkably fast, estimated at almost 500 kilometres per generation.
"However, I believe the impact of them in winter or early sown spring crops will be limited - but I could be wrong."
To report a sighting of fall armyworm call in Queensland call DAF on 13 25 32 or the Exotic Plant Pest Hotline 1800 084 881.
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