Jessica Lye A collaborative Grains Research and Development Corporation (GRDC) investment initiative is underway to compile what is known about fall armyworm and assess the information gaps that need to be filled in order to support the Australian industry.
Species of lepidoptera from the Spodoptera genus are notorious for being a destructive group in agriculture. The fall armyworm, Spodoptera frugiperda, is native to the Americas but has invaded and spread throughout Africa, the Middle East and Asia in recent years.
Fall armyworm is viewed by international agencies as a food security risk for many developing countries due to its highly polyphagous nature and feeding preference for the Poaceae family – including crop staples such as maize, sorghum, and rice. The impact of fall armyworm on small-holder farmers in these countries have mobilised governments and multi-national research and development organisations (such as the Food and Agriculture Organisation of the United Nations (FAO), CGIAR, CABI and US AID) and resulted in the development of several large-scale long-term strategies for reducing the impact of fall armyworm. These strategies have been developed alongside a large number of consortiums, farmer workshops, and best-management resources that are being implemented in locations across the globe.
Many readers would likely have first heard about fall armyworm when a detection of the biosecurity pest was made in January 2020 in the Torres Strait. By February 2020, fall armyworm had been detected on the Australian mainland. The pest is now considered endemic across parts of Queensland, Northern Territory and Western Australia and it has been determined that it is not technically feasible to eradicate.
Investigative work
The grains industry has identified a need to undertake a research, development and extension gap analysis for fall armyworm preparedness and management in Australia. This work is being led by Dr Olivia Reynolds, Research Lead at cesar and Graham Centre for Agricultural Innovation Adjunct Associate Professor alongside project partners Plant Health Australia, CABI, and the Queensland Department of Agriculture & Fisheries.
Once finalised, the gap analysis will provide a detailed review of the establishment, spread, impact, diagnostics, surveillance and management RD&E options relating to fall armyworm for the Australian grains industry. Further, the project will also deliver an Extension Plan to industry.
A knowledge gap that will be important to address through this research is that of the potential Australian fall armyworm host range – in particular, its potential to feed on pasture grasses in Australia. Work completed so far for the gap analysis has found a lack of verified knowledge on several host plants reported in the international literature.
Further, the host plant range in Australia is currently under scrutiny, with a significant question being whether the vast grass plains and broadleaf plants located throughout inland Australia are hosts of fall armyworm – as they are believed to be for Helicoverpa punctigera (Native budworm).
It will therefore be imperative to understand how such non-crop vegetation may contribute to the regional population dynamics of fall armyworm in Australia. If these areas harbour fall armyworm host plants, they could be important reservoirs, or sources of infestation for commercial crops with potential migrations triggered when the inland host grasses and/or broadleaf plants senesce.
The final RD&E gap analysis is due to be completed in August and will provide the grains industry with a basis for undertaking next steps to better understand and manage fall armyworm.
Be alert, not alarmed
While international coverage of fall armyworm does describe this species as a serious food security threat, it is important to understand that the Australian experience is likely to be very different. In countries characterised by small-holder farming operations and where maize is a staple food source, fall armyworm has had devastating impacts. However, Australian farming systems are appreciably different, with our farming systems allowing for greater economy of scale and much lower production of maize crops outside of for stock feed.
Further, Australia has a unique climate and flora, unlike that in any other country fall armyworm is found. We are only just beginning to research and observe how fall armyworm will behave in Australia and it will take time to understand how the pest will fit within ecological systems, what kind of pest pressure it will place on farms (and when), and how it will be most effectively (and sustainably) managed in certain crops.
To this end industry researchers, agronomists and growers are mobilising to bring answers to light as quickly as possible. And in the meantime, until growers become practiced at managing fall armyworm, being alert, but not alarmed is the message for the day – remembering that stories about this pest from neighbouring countries have arisen from a very different context and that production impacts are likely to differ in Australia.
It will be important to track the spread of fall armyworm overtime to ensure that at risk regions are equipped with the information that they need as soon as possible. If a suspected detection of fall armyworm is made in a new region contact your state department of primary industry to make a report or call the Exotic Plant Pest Hotline on 1800 084 881.
Acknowledgments
This article provides information on research activities undertaken as part of the GRDC investment CES2004-003RTX. Project partners include cesar, Plant Health Australia, CABI, and the Queensland Department of Primary Industries and Fisheries.
Thanks to Dr Olivia Reynolds, Francesca Noakes, Julia Severi and Jeevan Khurana for input in developing this article.
Cover image: Photo by Frank Peairs, Colorado State University, Bugwood.org, CC BY 3.0 US
