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Fall armyworm invasion danger
Fall armyworm is a threat to a wide range of cereal and vegetable crops and is spreading across New Zealand.
JOYCE WYLLIE
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A new exotic larvae may be lurking under leaves in our gardens and paddocks. This unwanted pest, the fall armyworm (FAW), is native to the Americas but since 2016 has been spreading around the world.
FAW feeds on over 350 plant species, preferring cereals and vegetables like corn, beans, asparagus, peas, kūmara, brassicas, onions, lettuce, and tomatoes.
The adults and larvae are highly mobile, with moths able to fly up to 500km before laying eggs. Newly hatched larvae form a strand of silk and become windborne. They can also travel on storm fronts, and it is possible that is how they arrived in New Zealand from Australia. FAW have been found in maize crops on the West Coast, so it is important that Golden Bay gardeners and farmers are aware.
Adult moths are nocturnal with brown-grey forewings and cream-coloured hind wings, and are most active during late summer/early autumn. Eggs are pale yellow, laid on leaves in masses of 150 to 200, covered with a protective layer of scales which appears as a silky furry substance.
Young larvae are green-brown, becoming darker as they mature. The head has a distinctive pale “Y” marking and four black dots on the last body segment, forming a square shape.
Larvae feeding on stems and leaves cause damage and if infestation is severe, plants are defoliated. On corn, the larvae attack the ear, silks, and cobs. Graeme McCleely from PGG Wrightson reports that they are checking maize crops regular-ly and working alongside Ministry for Primary Industries (MPI), but no FAW has been found here.
It is important that any suspected findings are reported to Biosecurity New Zealand, as early detection will help protect New Zealand’s primary sector. It is not something we want to discover here, but farmers and growers are encouraged to look under leaves and be vigilant.
If any unusual symptoms are seen on plants or there is a possible sighting of the pest as an adult, eggs, or larvae, MPI request that you take a photograph and call the Exotic Pest and Disease Hotline ph 0800 80 99 66, or report online at report.mpi.govt.nz/pest.
