Fall armyworm

Fall armyworm  (FAW; Spodoptera frugiperda) was first detected at locations in the northern parts of Queensland, Northern Territory and Western Australia. It has been determined that it is unfeasible to eradicate this pest and it is now classified as an established pest in these areas.

While these areas are likely to host FAW populations in crops, pastures, weeds and native grasses, it is difficult to know just how significant a pest FAW will be in the different crops within these areas or regions further south. It will also be challenging to predict how Australia’s climatic and vegetation zones will influence the timing and magnitude of possible future FAW migrations within Australia.

Plant Health Australia received funding to develop resources to fill the gaps in knowledge and research about how the pest behaves and can be managed in Australia.

Fall Armyworm Continuity Plan for the Australian Grains Industry

Fall Armyworm Continuity Plan for the Australian Grains IndustryThe Fall Armyworm Continuity Plan was developed for use by professionals, specialists and consultants to prepare localised and industry specific communication and extension material.

The plan focuses on the grain industry and provides:

  • background information on the current knowledge and status of fall armyworm (FAW; Spodoptera frugiperda) in Australia
  • key considerations in developing localised management strategies
  • future research and development for the Australian grain industry.

The purpose of the plan is to provide a reference point and a basis for industry to build upon when designing resistance management strategies, area wide management plans, crop-specific management manuals, and other extension materials such as audio and visual products for the management of FAW within Australian broadacre farming systems.

Acknowledgement: This is a Grains Research Development Corporation investment initiative led by Cesar with project partners Plant Health Australia, Centre for Agriculture and Bioscience International, and the Queensland Department of Primary Industries. Contract code: CES2004-003RTX.

Boosting national research and development for Australia’s ongoing management of Fall Armyworm

Plant Health Australia is working with the Department of Agriculture, Fisheries and Forestry in boosting the funding for critical national R&D to minimise the damaging consequences caused by Fall Armyworm to Australian plant industries.

The program has identified the critical gaps in fall armyworm knowledge of national interest, through a National R&D forum and has prioritised and developed the following four projects:

  • Genomic insight of FAW movement in Australia(CSIRO, Wee Tek Tay), seeking to (1) apply established population genomic analysis pipeline to understand the genetic contribution of new migrants to the established Australia FAW populations, and (2) to understand the level of population connectedness between Australian FAW populations. (Project budget $110,000 plus GST)
  • Understanding the key market drivers that will underpin the development of an Insecticide Resistance Management Strategy for FAW. (ICAN, Mark Congreve), seeking to understand existing crops x region x insect pest occurrence for the identified important host crops for FAW. Current insecticide use by region will be explored, including documenting any successful IRMS that are already in place for other pests. The project will also seek to explore how FAW management is likely to change insecticide use patterns. (Project budget $110,000 plus GST)
  • Surveying and testing locally occurring insect viruses for use in Fall Armyworm management, (QDAF, Ian Newton), seeking to collect local endemic insect viruses found in Fall Armyworm and related insects and determine if local endemic viruses are more effective on FAW than imported commercial virus based biopesticides. (Project budget $110,000 plus GST)
  • Rapid real-time simulation of wind-assisted long-ranged dispersal of fall armyworm in Australia. (CESAR, James Maino), seeking to improve existing predictive models for Australian fall armyworm seasonal activity and long-distance dispersal predictions through enhancements that incorporate wind-assisted long-distance migrations. (Project budget $109,774 plus GST)

Project Summaries

Genomic insight of FAW movement in Australia

CSIRO, Wee Tek Tay

Native to the North and South Americas, the fall armyworm (FAW) Spodoptera frugiperda gained global attention in 2016 when its presence in western sub-Saharan (Nigeria, Benin, Togo, Sao Tome) was confirmed. Since then, this highly polyphagous insect pest with high flight ability has been recorded in over 90 countries that resulted in significant economic losses and devastated crops (i.e., maize, sweet corn, sorghum, barley, rice, ginger, sugarcane). The current hypothesis, based on partial single gene analyses (e.g., TPI, mtCOI) surveyed from invasive populations detected low genetic diversity, and when considered together with official FAO/IPPC reported detection dates, suggested an incursion pattern involving a single introduction of both the corn preferred (Sfc) and rice-preferred (Sfr) FAW, and which spread from western Africa to Asia, the Far East and the Oceania regions.

Genomic analyses of globally representative populations from Africa and Asia however, detected high level of genetic diversity, with signature of introgression between Sfc and Sfr in both native and invasive populations, as well as evidence of multiple introductions. Furthermore, significant response differences to insecticide bioassays in invasive FAW populations highlighted gaps in our knowledge relating to the FAW invasion biology. Australia represents one of the most recent and final frontiers for the FAW, there is therefore a need for on-going monitoring of population genetic connectivity with Asian and African populations (especially since these populations were likely exposed to different insecticide/chemical management regimes), to understand their gene flow patterns, and how genetic contributions from new migrants could impact on pest populations’ local adaptation to the Australian agricultural landscapes. The presence of novel insecticide resistance alleles in S.E. Asia and differential resistance to insecticides both between Australian and non-Australian FAW populations, suggested significant genetic diversity in invasive populations that remained poorly understood.

The proposed project will aim to categorise current genetic diversity in Australia’s FAW populations at both spatial (i.e., between WA, NT, Qld, NSW) and temporal (i.e., Year 1 and Year 2 post incursion) scales, and to provide insights to potential genetic contributions from invasive FAW populations, especially in the Year-2 post incursion populations. Knowledge gained from this project will help identify and contribute to developing national FAW management strategies to benefit Australia’s horticultural and agricultural sectors.

Project 1: Final Technical Report – Genomic insights of FAW

Understanding the key market drivers that will underpin the development of an Insecticide Resistance Management Strategy for FAW

ICAN, Mark Congreve

It is known that the preferred host for FAW is maize / sweet corn. However, FAW can also cause economic damage to a wide range of broadacre and horticultural crops. FAW is expected to be present year-round in many tropical / sub-tropical environments, while at more southerly locations in Australia, populations are likely to reduce in winter and then rebuild over spring and summer and are likely to be at most damaging levels in late summer.

While a fully integrated management program of tactics will be required to manage FAW, the judicious use of insecticides across a wide variety of host crops will be an important pillar underpinning control. Insecticide management is further complicated by the fact that:

  • FAW populations entering Australia in 2019 were already resistant to certain insecticide modes of action
  • Some insecticides that are effective against FAW are not registered in all host crops
  • Insecticides have differing selectivity to beneficial predators and parasitoids (beneficials), and the importance of individual beneficial species changes between crop types
  • Insecticide use targets a range of insect pests. The use of insecticides targeting FAW needs to be complementary with other insecticide management programs in the crop and the region of use
  • A significant increase in insecticide use targeting FAW is likely to place further resistance pressure on key insecticides.

Experience both in Australia and more globally has shown that frequent use of insecticides can lead to the development of resistance to that mode of action in potentially a wide variety of crop x pest combinations. FAW populations are known worldwide to be able to rapidly select for insecticide resistance.

An expected strategy underpinning the effective management of FAW in Australia will be the requirement to develop regionally based Insecticide Resistance Management (IIRM) strategies for key host crops and insect targets.

To facilitate development of these regional IRM strategies, detailed market research is required to understand the major host crops x geographic region; when these crops are grown within the region; current insecticide use patterns for other pests; predicted FAW pressure; and how FAW is likely to change existing insecticide use patterns and if the adoption of increased insecticide use targeting FAW is likely to significantly impact beneficial populations resulting in ‘flaring’ of other insect pest species.

This project proposal proposes research to understand existing crops x region x insect pest occurrence for the identified important host crops for FAW. Current insecticide use will be explored, including documenting any successful IRMS that are already in place for other pests. The project will also seek to explore how FAW management is likely to change insecticide use patterns.

Project 2: Final Technical Report – Understanding key market drivers for resistance management

Surveying and testing locally occurring insect viruses for use in Fall Armyworm management

QDAF, Ian Newton

Fall Armyworm (FAW) has recently invaded Australia and has swiftly spread across northern Australia and as far south as Victoria. It is a major pest of sweetcorn, maize sorghum and other crops. It is resistant to most of the older chemical pesticides and is proving very difficult to manage resulting in crop failures. Newer chemicals are expensive and only work well with good spray coverage and timing. Furthermore, there is a high risk that FAW will also develop resistance to these newer chemicals. In order to manage FAW in a sustainable way, alternative non-chemical management options are also required. Researchers are working on FAW through a multipronged approach, including chemical control, chemical resistance management, semiochemicals, monitoring and thresholds, cultural and biological control. A potential biological control option is the use of Entomopathogens (e.g. fungi and viruses) as a biopesticide. Other projects are researching biological control options including surveys for parasitoids and fungal pathogens.

Endemic virus-based biopesticides have been used for managing other similar Australian pests (e.g. Helicoverpa armigera) and may offer some options for managing FAW. Such products have a perfect IPM fit, because they have no side effects on predators, parasitoids and pollinators; no environmental, health or residue issues; and no resistance issues. Imported virus based Nuclear Polyhedrosis Virus (NPV) biopesticides have been developed overseas as commercial biopesticides for FAW (e.g. Fawligen™ and Spodovir Plus™), however overall, there is very little efficacy data on these products and they may not work on strains of FAW in Australia. Viruses have previously been found in Australia on related armyworms (other Spodoptera species) and DAF has recently completed molecular characterisation on virus isolates from the DAF collection. More recently, local NPV viruses have been found in the newly established FAW populations in Queensland. More endemic virus isolates are likely to be found and these virus isolates will clearly be causing FAW mortality under Australian conditions.

These previous and more recently found virus samples have been collected and stored by DAF researchers. In this project, we will survey wild FAW for new endemic virus strains and conduct laboratory bioassays to determine the efficacy of the endemic viruses (including isolates from the historical DAF collection) against FAW, and compare these with the imported commercial biopesticide virus strains. If endemic virus isolates are found to have a greater efficacy against FAW than imported products, they could provide a more effective management option and a superior commercial product. This would lead to improved (in terms of efficacy and reliability) management options for growers and less reliance on chemical pesticides.

Project 3: Final Technical Report – Survey of local insect viruses for FAW management

Rapid real-time simulation of wind-assisted long-ranged dispersal of fall armyworm in Australia

CESAR, James Maino

The fall armyworm (FAW, Spodoptera frugiperda, is a lepidopteran pest that feeds in large numbers on the leaves, stems and reproductive parts of more than 350 plant species, causing major damage to economically important cultivated grasses such as maize, rice, sorghum, sugarcane and wheat but also other vegetable crops and cotton. FAW was first reported in Australia in January 2020 in the Torres Strait and by the end of the year had spread to New South Wales and northern Victoria. In this time, it has caused significant damage to production industries, in particular maize, popcorn, and sweetcorn, but impacts to other crops such as sorghum, as well as pastures have also been observed.

The large dispersal potential of FAW adults, wide host range of immature feeding stages, and unique environmental conditions in its invasive range creates large uncertainties in the expected impact on Australian plant production industries and natural environments. Enhanced predictability of FAW population movement across large spatial scales will support targeted surveillance, monitoring and management, and thus reduce the impact of FAW in Australia. While some preliminary preparedness work on FAW has been undertaken in Australia, including a predictive model for seasonal activity potential (Maino et al 2021), this model did not consider the role of wind-assisted long-distance dispersal, and made the simplifying assumption of random long-distance dispersal.

Through this project, we leverage state-of-the-art physical models for wind dispersal of particles (HYSPLIT) but overcome key limitations (computationally intensity, lack of biological processes, and inability to produce fast grid-based predictions) which make them unsuitable for an efficient early warning system. We will extend preliminary predictive modelling research on the seasonal occurrence of fall armyworm in Australia through the GRDC project (CES2004-003RTX) “Preparedness and Management for fall armyworm (Spodoptera frugiperda)” which is already being used in other applications, such as the development of novel pesticide resistance management strategies in FAW. To summarise the approach, we will 1) compile daily gridded wind data, 2) develop a rapid simulation cellular automata technique for wind-assisted dispersal, 3) validate the approach against state-of-the-art (but computationally slow and biologically unrealistic) HYSPLIT models, 4) incorporate wind-dispersal module into existing FAW simulation model, and 5) make findings widely available through a technical publication and user-friendly web interface.

The incorporation of wind-assisted long-ranged dispersal into existing Australian fall armyworm (FAW) models will represent a foundational piece of work necessary for early warning predictive capacity for migrations across the Australian continent. This predictive ability will help target monitoring and management activities across cropping, pastoral, rangeland and non-agricultural areas, but may also support identification of high-risk pathways for overseas FAW biotypes that may possess novel traits (e.g. chemical resistance) not currently present in Australian populations.

Project 4: Final Technical Report – Rapid real-time simulation of wind-assisted long-ranged dispersal of FAW in Australia

Plant Biosecurity Research Initiative Podcasts

Fall Armyworm podcastsPBRI Podcasts feature interviews with growers and agronomists on their first-hand experience in managing new and emerging pests, leading Australian researchers on their latest findings and observations and international experts who share their experiences and learnings.

Each episode runs for about 30 minutes, and you can listen in any order you want.

The first series of PBRI Podcasts is on fall armyworm. It explores the experiences and observations of experts from around the globe and here in Australia as we take on this invasive pest. Throughout the series, host Chris Brown delves into the biology and behaviour offal armyworm and explores how we can minimise its impact.

The episodes are:

  • Episode 1: Fall armyworm biology and ecology in subtropical and temperate US
  • Episode 2: Applied fall armyworm management in row crops and pastures in Texas
  • Episode 3: Active response to fall armyworm in South Africa
  • Episode 4: FAO’s global action for fall armyworm control
  • Episode 5 : Field observations of fall armyworm in north Queensland
  • Episode 6: Footprints in the paddock – approaches to scouting, developing thresholds and tips to familiarise yourself with Fall Armyworm.
  • Episode 7: Field observations of Fall armyworm in northern Western Australia
  • Episode 8: Trial observations and laboratory findings on fall armyworm in the Northern Territory
  • Episode 9: Could Fall armyworm have been present in our region for longer than first thought? Tracing the spread.

The podcasts are available on the PBRI website

Related information

Preparing Australia to manage fall armyworm (Farm Biosecurity)

Fall armyworm and other exotic armyworms (Australian Government Department of Agriculture, Water and the Environment)

Fall armyworm found in Oz (Farm Biosecurity)