Grain growers in New South Wales are advised to check and monitor crops for fall armyworm (FAW), with the pest being detected as far south as the Lower Namoi region.

The first detection of FAW (Spodoptera frugiperda) in northern NSW was on September 23 in a pheromone trap between Moree and Boggabilla, and additional moths were found in traps east of Narrabri and west of Wee Waa last week.

Fall armyworm have a high reproductive rate and dispersive capability. Some estimates suggest the pest can travel around 100 kilometres in a night and 500km in a generation.

Grain growers, agronomists and advisers across the state are now advised to inspect and monitor establishing summer crops for signs of fall armyworm damage and the presence of larvae.

Early symptoms include ‘windowing’ of leaves where larvae have hatched, and small ‘shot holes’ in leaves as the larvae start to grow.

Identification of recently emerged larvae can be difficult in the field, but by the time larvae reach the second to third instar stages the features that allow diagnosis become more obvious.

For small larvae, the NSW Department of Primary Industries (DPI) recommends retaining FAW samples along with food sources, such as host crop leaves, and allowing them to grow to enable photographs to be taken. In most cases, identification will be possible from clear photographs.

Images of suspected FAW can be sent to NSW DPI Biosecurity for assistance with identification:

• Email biosecurity@dpi.nsw.gov.au with a clear photo and your contact details
• Growers who find FAW should notify the Exotic Plant Pest Hotline via 1800 084 881 or through an online form.

Grains Research and Development Corporation (GRDC) Manager Biosecurity Jeevan Khurana said NSW DPI had about 45 traps in place across northern NSW, with plans for additional traps south of Dubbo to the NSW/Victorian border.

“Traps are in place to give authorities and industry insight into where and how rapidly the pest is spreading, and growers are strategically placed to play a role in monitoring and assessing the impact at a farm level,” Dr Khurana said.

“Based on Australian experience with fall armyworm thus far it has a preference for maize and sorghum and it has also been found in some pulses and pasture.

“While GRDC has research underway that will provide more insight into this new pest, we know that it is a migratory species that can utilise prevailing winds. It is expected that populations in the north will persist year-round while seasonal migrations into more southerly regions will occur in warmer months.

“It is difficult to predict exactly how Australia’s climatic conditions will influence the timing and magnitude of fall armyworm migrations, but it will not survive frosts or temperatures below around 12 degrees Celsius, providing some indication of the likely endemic and migratory range.”

If FAW is detected there are key steps growers and advisers should consider in their response.

These include:

• Assess – consider the activity in your region, such as by reviewing available trap results
• Find – regularly monitor crops
• Identify – seek assistance with accurate identification as needed
• Thresholds – refer to economic thresholds where available to assess triggers for management action
• Enact – make informed selection of management tools, and only spray when economic thresholds are reached.

Growers can purchase and set up their own FAW monitoring traps. For more information they should consult with their retail agronomist.

Further information on identification, treatment options and resistance management is available at:

NSW Department of Primary Industries

Fall armyworm: a crop invader on the march

The Beatsheet

The first six episodes in a podcast series of nine on the impact and management of fall armyworm have been released by the Plant Biosecurity Research Initiative (PRBI).

Contact details

Contact

Bill Gordon, NSW DPI, Grains Biosecurity Officer
0428 133 944
billy.gordon@dpi.nsw.gov.au

Jeevan Khurana GRDC Manager Biosecurity
0428 104 946
Jeevan.khurana@grdc.com.au

Toni Somes, GRDC Communications Manager - North
0436 622 645
Toni.somes@grdc.com.au