Sun, Mar 12, 2023 5:30 AM

Have You Seen the Fall Armyworm?


Eloise Martyn

A destructive and unwanted plant pest has arrived for the first time ever in the South Island. The Ministry of Primary Industries are asking people to be on the lookout for it and to report any sightings - have you seen the Fall Armyworm?

The Fall Armyworm is a destructive plant pest that can feed on over 350 plant species, but by far their favourite snacks are maize and sweetcorn crops. They also enjoy asparagus, beans, peas, brassica, onions, kumara, lettuce, tomatoes, eggplant and capsicum. It is called 'armyworm' because in its larval stage, individuals gather in huge masses ('armies'), which then destroy large crops.

It is native to America and since 2016 has spread to Africa, Asia and parts of Australia. As a hitchhiker pest that can be blown many hundreds of kilometres on storm fronts, it has been on New Zealand’s Biosecurity radar for some time. Farmers and growers in the upper North Island began reporting larvae finds in September/October last year. Recently there have been three confirmed findings in maize paddocks on the West Coast, which is the first time it has been detected in the South Island. The number of confirmed findings had increased to 56 (as of January 14). It' s arrival has arable and vegetable growers worried.

“The Fall Armyworm really affected crops in China when it appeared there so it’s not good news to see it in the South Island and so close to our region” says Stephen Todd, President of Nelson Federated Farmers and dairy farmer from the Tutaki Valley in Murchison. In the past four years, the Fall Armyworm, has caused extensive economic damage across Africa, South Asia and Southeast Asia. “Many dairy farmers like myself have small maize crops so we need to be on the lookout”

The Ministry for Primary Industries biosecurity response is currently focusing on identifying key areas to understand the geographic spread and scale of the Fall Armyworm incursion. “This is a new pest to us; we need to do everything we can to control it starting with reporting any sightings so we can work out exactly where they are” Stephen explains “Once it turns into a moth it can travel a long way each night so it has the potential to spread at high speed”. In fact, the insect has the ability to fly more than 100km per night and in a small country like New Zealand it will not take long for it to be nationwide.

While this is a new pest to New Zealand treatment options are available and include several types of insecticides, many of which are already used in New Zealand for other kinds of pests, as well as pheromone traps. “At this stage our main tools of defence are detecting the pest early, spraying at the right time and reporting any findings” States Stephen “If you have this pest removing crops will not control the Fall Armyworm but by reporting it you will get good advice on how to manage it.”

Fall Armyworm in the whorl of a maize plant in Hokitika. Photo: Supplied.

Messaging is not just targeted at arable and horticulture growers, all farmers, grower, lifestyle owners and gardeners need to be on the lookout and actively scouting for caterpillars. “Now it’s here we won’t be able to get rid of it so we need to look at how we can control it and prevent it wreaking havoc on our agriculture sector” Stephen states “I’m sure if your neighbour had it on their property you would want to know. Everyone needs to play their part, report findings and support those who have invasions”.

If you suspect you have the Fall Armyworm on your property or in your garden, please refer to the contact information below.

  • Since this is an unwanted organism all findings must be reported to MPI: or using the app , by email to or by freephone 0800 80 99 66. There are no negative consequences to growers for reporting, as this pest will not be controlled by removing crops.
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