Information about Fall armyworm (FAW) and its management in grain crops has been consolidated into a reference document for use by Australian consultants and other industry professionals.

Produced with investment from the GRDC, the Fall Armyworm Continuity Plan was compiled by sustainable agriculture research organisation cesar, PlantHealth Australia, the Centre for Agriculture and Bioscience International, and the Queensland Department of Primary Industries.

FAW (Spodoptera frugiperda) is a highly migratory, invasive pest that was first reported in Australia in February 2020 and quickly established across parts of northern Australia’s tropical and sub-tropical regions, including northern Queensland, the Northern Territory, and northern parts of Western Australia.

More recently, the pest was first detected in New South Wales in late September 2020, north of Moree. Subsequent detections were made east of Narrabri and west of Wee Waa in October 2020.

Australian biosecurity organisations have determined it is unfeasible to eradicate.

Olivia Reynolds, cesar research lead, says the national Fall Armyworm Continuity Plan would be an important resource to aid industry in dealing with this exotic pest at this early incursion stage.

Dr Olivia Reynolds, cesar Research Lead

“It is intended as a reference document for professionals, specialists and consultants in preparing more localised and industry-specific communication and extension material,” Dr Reynolds says.

“This plan compiles information from international literature and expertise and provides a solid background of knowledge on the pest, which will support the development of effective management strategies, plans and information sharing networks.”

Areas addressed include FAW biology and behaviour; spread, impact and seasonal dynamics; identification and scouting; management considerations; resistance management; and FAW extension.

The plan includes a ‘Quick Guide’ synthesising essential baseline information on the biology and behaviour of FAW, together with symptoms of plant injury and management strategies.

Dr Reynolds says the Quick Guide outlined how FAW could travel long distances into more temperate or arid regions that were unfavourable for permanent populations.

“FAW may travel to these southerly regions when seasonal conditions permit, and it might produce several generations (and can therefore still cause damage) but is unlikely to be able to maintain year-round populations in more southerly regions,” she says.

Dr Reynolds says FAW completed its lifecycle in about 30 days at optimal temperatures and would be able to complete multiple generations each year in Australia’s subtropical and tropical climatic regions.

“Plants within the grass family (Poaceae) including maize, sweetcorn, sorghum and C4 pastures are favoured hosts of FAW,” she says.

“The rate of FAW population growth will increase during warmer months and decrease during colder months, and migrations into southern regions are predicted to generally commence from spring.”

Other key points include:

• Maize, sorghum and other crops can tolerate some level of damage to leaves without yield impacts.
• It is difficult to distinguish the eggs and early instar larvae of FAW from other Spodoptera species found on grains crops. Older FAW larvae have distinct markings that enable them to be more readily distinguished from other similar pests.
• Monitoring for FAW eggs and larvae should involve visual inspection of the crop or host plant.
• In maize/sweet corn, young leaf tissue is more suitable for larvae growth and survival than mature leaves. In mature maize plants, larvae tend to settle and feed in the ear zone.
• Early planting of maize, where feasible, may reduce later season FAW damage in this crop.
• Fortunately, many of the products registered for Helicoverpa control will also be effective against FAW, and incidental control will occur at certain stages of crop development.
• Getting the crop off to a good start with sound agronomy and crop nutrition will ensure plants are more resilient.
• Managing volunteers in fallows, and other green bridge sources, will reduce pressure, thereby reducing local populations of FAW.
• Avoiding sequential plantings of preferred crops such as maize and sorghum, will help reduce local populations of FAW.

The development of the Fall Armyworm Continuity Plan is part of a GRDC-invested project, led by cesar, investigating FAW biology, spread and establishment potential, as well as options for improving industry capability to manage the pest.

GRDC is also collaborating with other plant-based research and development corporations, the Department of Agriculture, Water and Environment, the Queensland Government Department of Agriculture and Fisheries, and Plant Health Australia to ensure an effective response to FAW through targeted investments.

Growers are encouraged to monitor crops to identify signs of infestation early. If you suspect FAW, report immediately to the Exotic Plant Pest Hotline on 1800 084 881.

More information: about FAW is available on the GRDC fall armyworm portal; Dr Olivia Reynolds, cesar Research Lead oreynolds@cesaraustralia.com; Dr Jeevan Khurana, GRDC Manager Biosecurity, Jeevan.khurana@grdc.com.au