Fall armyworm marches across Australia

KEY POINTS ABOUT FAW

  • This introduced pest has the potential to destroy agricultural and horticultural crops and will also be found in gardens.
  • The adult moth is nocturnal and can fly 100km in a night and up to 500km in its lifetime.
  • Egg clusters can hatch in as little as two to three days in warm conditions.
  • Some 350 plant species are targeted by this pest, including many commercially important crops.
  • It has the potential to spread across Australia, especially during summer.
  • It is difficult to control.
  • It’s here to stay!
Fall armyworm moth. The pest can fly 100km in a night.
The larvae feeding on corn foliage. Photo Adobe Photo Stock

The worldwide pest, fall armyworm (Spodoptera frugiperda), also known as FAW, arrived in Australia in February 2020 at that same time the world’s attention was focused on the spread of COVID-19. Jennifer Stackhouse reports on the latest information.

Like the virus, this moth and its larva spread rapidly from where it was first discovered on Cape York. It is now active across much of northern Australia from Bundaberg to Geraldton, echoing its predicted distribution.

Potential distribution of fall armyworm as shared on a recent webinar on the pest. The red, orange and yellow colours indicate areas where fall armyworm will establish. The green and pink areas show its likely spread in summer. The pest has already travelled across northern Australia as predicted.

So far in Australia, fall armyworm (FAW) is feeding mainly on corn (foliage and cobs) however it has also been found on rockmelon (fruit) and has the potential to feed on around 350 species including ornamentals.
FAW spread from South America through the United States before heading across the seas to Africa in 2016. From Africa it headed north to parts of the Middle East, much of Asia and now Australia.
Although it is a pest of warm climates, its spread is not restricted to the tropics and subtropics. During summer it can move into colder areas. Each year it regularly heads north from Florida and Texas in the US to Ontario in Canada. However, it doesn’t survive diapause in cold zones. With this pattern of activity, there is every chance that FAW will reach all parts of Australia this summer and evident in gardens and parklands. It could also spread to New Zealand.

The life cycle of fall armyworm speeds up as the weather warms. This diagram was shared during the AUSVEG webinar in September.

Online webinar update
Australia’s peak vegetable body, AUSVEG, held a webinar in late September to update horticulturists about FAW, with experts explaining how it can be identified and which chemical controls are effective.
The webinar’s take home message was that FAW has come to stay and we need to learn how to manage it in a sustainable way.
As the insect is resistant to Group 1 chemicals and pyrethrum gives poor control, spinosad is recommended for home garden control. In cropping, chemicals including Match and Proclaim are recommended with pheromone traps to monitor for activity.
The insect has a rapid life cycle with eggs hatching in just a few days. A key control, especially on sweet corn and maize, is to spray the foliage where egg clusters are laid. Time sprays just prior to hatching to kill the larvae when they are small and before they disperse over the plant. Work is also underway to identify possible native biological controls.

More information
To view the entire FAW webinar online, follow this link.

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