Fall armyworm. Photo: Russ Ottens, University of Georgia, Bugwood.org.

AN East Gippsland seed production manager’s vigilant scouting and crop surveillance in maize has helped detect fall armyworm in Victoria for the first time, arriving in Orbost.

After being found in Queensland for the first time in January 2020, fall armyworm has rapidly spread across Australia and is now also in New South Wales, the Northern Territory and Western Australia.

Gippsland Seed Services production manager Marni Riordan placed traps out to check for fall armyworm after seeing firsthand the impact the pest was having on crops in Queensland.

“At Gippsland Seed Services, we crop maize, sweet corn and popcorn for seed, all of which fall army worm could have a large impact on,” Ms Riordan said.

“When it was reported north of the Victorian border, we wanted to know when it was in Victoria so we can best change our practices to manage the pest.”

The traps caught some moths, which Ms Riordan quickly sent to Agriculture Victoria for diagnostics, where some were confirmed as fall armyworm. Agriculture Victoria plant pests and diseases manager Chris Pittock said the role of the community in reporting pests was crucial for not only for government to understand the situation, but also for community and industry to have the right information to manage the pests.

“It’s not surprising fall armyworm had been found in Victoria after rapidly spreading across Australia this past year,” Dr Pittock said. “Fall armyworm has adapted to warm tropical and sub-tropical areas in northern Australia and can migrate rapidly and be spread by storm events.

“Victoria will likely see flights of adult moths in future years from mid-spring through summer and into autumn, as we have seen this summer. However, as Victoria has a colder winter, we anticipate those numbers to mostly die out in cold weather.

“Thank you to the Ms Riordan for immediately reporting this pest to Agriculture Victoria. Reporting is a key part of a strong biosecurity system to identify new exotic pests and support surveillance.”

Due to the insects’ reproductive capacity, ability to fly long distances, wide host range, spread of known infestations and potential for re-infestation from Australia northern neighbours, it was nationally decided in May that it was not feasible to eradicate this pest from Australia.

Fall armyworm feed on maize, sweet corn, sorghum and sugarcane, and experiences in Queensland have also shown a high preference for feeding on corn, even though wheat, millet and sunflowers were nearby.

“As there have already been detections in Australia, we in Victoria can benefit from learning about what has happened and the experiences of other locations around Australia,” Dr Pittock said.

“There has already been significant national effort towards preparedness and management of fall armyworm, particularly in grains and cotton.”

Dr Pittock said if agronomists and farmers found fall armyworm on their property, they should seek professional advice for treatment and management and report locations to Agriculture Victoria.

“The adult moths are 32mm to 40mm in length wing tip to wing tip, with a brown or grey forewing and a white hind wing. Male fall armyworms have more patterns and a distinct white spot on each of their forewings.

“The eggs are pale yellow in colour and clustered together in a mass, which often contain 100 to 200 eggs per mass. Egg masses are usually attached to foliage with a layer of mould/silk-like furry substance.

“The newly hatched larvae are light coloured with a larger darker head and then develop white stripes lengthwise as the larvae darken and grow to about 34mm in length.” This detection comes as 2020 was marked as International Year of Plant Health globally, a reminder that we must work to protect our plants from the impacts of pests and diseases. Anyone can report fall armyworm by contacting the Agriculture Victoria customer contact centre on 136 186 or complete the online form at forms.bio.vic.gov.au/public-reporting.