By Dr Ramesh Raj Puri, Extension Officer & Dr Heidi Parkes, Senior Research Scientist, Department of Agriculture and Fisheries Queensland

Fall armyworm (FAW) is a major pest for sweet corn growers and a threat to other vegetable crops like capsicum and ginger. Continued reliance on chemical insecticides to manage FAW concerns growers, who are worried about insecticide resistance, increased production costs and threats to integrated pest management.

This concern has driven interest in biological alternatives like parasitoids, biopesticides, and more resilient cropping systems to protect plants from FAW damage. Whilst Australian research is critical, it’s also worth looking overseas at the tools and strategies adopted by farmers exposed to the FAW pest for many years.

FAW was first detected in Australia in the Torres Strait in January 2020 and has since spread to every state and territory except South Australia. It has caused significant crop losses in sweet corn, maize and sorghum, and has affected other horticultural, grain and fodder crops to a lesser extent.

FAW infestations of maize and sorghum reached record levels in Queensland and northern New South Wales in 2024, and expansion into winter cereals and pasture grasses raised concerns about the pest’s growing impact across industries.

The Hort Innovation co-funded National fall armyworm innovation system for the Australian vegetable industry (VG22006) has held a series of webinars aimed at bringing the latest in fall armyworm knowledge from across the globe to Australian industries.

On 18 July, Queensland Department of Agriculture and Fisheries (DAF) extension officer Dr Ramesh Puri hosted the webinar ‘Integrated Pest Management for fall armyworm: Experiences from Africa’ in collaboration with the International Centre of Insect Physiology and Ecology (icipe) in Kenya. During the session, icipe scientists Dr Sevgan Subramanian and Dr Amanuel Tamiru talked about their work on IPM strategies for FAW and push-pull farming systems.

Dr Sevgan presented sustainable solutions for FAW management by smallholders in Africa, detailing effective strategies and advancements in monitoring and managing the pest (Figure 1).

FIGURE 1. Strategies for managing Fall armyworm in Africa. Source: Dr Sevgan Subramanian, icipe, Kenya

Dr Tamiru discussed the chemical ecology underpinning the push-pull farming system, which has proven to be a groundbreaking approach for combating invasive pests like FAW in Africa (Figure 2).

FIGURE 2. Push-pull field showing maize intercropped with push crop, greenleaf desmodium (D. intortum), and pull crop, Brachiaria cv mulato II, as a border crop. Source: Dr Amanuel Tamiru, icipe, Kenya.

The FAW situation in Africa

African agriculture is characterised by smallholder farmers practising mixed cropping systems, typically on less than 1ha. Maize productivity is low compared with Australia due to factors like poor soils and rainfed cultivation. FAW infestation levels in Africa have significantly decreased since the initial invasion in 2016. The stabilisation of FAW pressure could be due to increased awareness among maize growers about the need for timely and need-based management approaches, the practice of mixed cropping rather than monocropping, and the widespread prevalence of natural enemies.

However, it is too early to call the management of FAW in Africa a success. Pest pressure remains high in agroecological zones, and infestation levels are particularly high in late-planted maize. Whilst African researchers have tested various tools and technologies to better manage FAW including monitoring, push-pull systems, biopesticides, biorational pesticides and natural enemy release, adoption of these practices has been slow.

Biological options used in Africa

New associations of FAW with natural enemies of other prevalent armyworms have been commonly observed in new invasion regions in Africa and Asia. These new associations of FAW with local parasitoids and predators need to be documented to support their conservation and augmentation. Similarly, biopesticides such as Metarhizium anisopliae and baculoviruses effectively manage FAW if integrated with other IPM strategies. These biopesticides are commercially produced, and their efficacy is tested in the field. However, their adoption rates are low due to high costs in Africa, and efforts to build capacity for localised production are ongoing.

Push-pull farming systems in Africa

Push-pull is an agroecological farming system that exploits natural insect-plant and plant-plant interactions to manage crop pests. icipe’s push-pull system uses the forage legume Desmodium as an intercrop to repel pests and attract natural enemies, and a border of forage grass as a trap crop to lure pests away.

Based on their experience with maize, they have found 5 percent cob damage in the push-pull system compared with up to 20-25 percent in the monocrop maize control under reasonable pest pressure (noting that cob damage could also be caused by pests other than FAW, including birds). The system has not yet been tested with sweet corn.

Push-pull farming – which has been adopted by over 350,000 smallholder maize growers in Sub-Saharan Africa – also enhances soil health and livestock integration. Some farmers use pesticides in push-pull systems, but many do not.

Lessons for managing FAW Australia

What can Australian growers, agronomists and researchers learn from Africa’s experience with managing FAW?

Combining agroecological approaches and biocontrol options could provide sustainable and affordable solutions to manage maize pests such as FAW.

• FAW management could be improved with better FAW monitoring, adoption of mixed cropping systems for greater resilience, cataloguing and conserving natural enemies of FAW, and promoting good agricultural practices that allow maize to compensate for FAW damage.
• Understanding FAW’s migratory or resident nature in new invasion zones such as Africa and Australia is critical for fine-tuning FAW management strategies.
• Maize grown in a diversified cropping system, such as maize-legume intercropping or push-pull systems, is more resistant to FAW than maize grown in a monocrop system.
• There is an opportunity to adapt diversified maize cropping systems from small to large-scale maize production

FIND OUT MORE
A full webinar recording is available on YouTube.