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Fall armyworm presence in NZ
Fall armyworm (FAW) is thought to have been carried on storm fronts from Australia and arrived in New Zealand around February 2022. There have been isolated detections since then. Most of the finds have been over the summer and autumn period because the fall armyworm thrives in warmer climates.
In the warmer months of spring and summer, we encourage everyone to look for signs of FAW, particularly on maize and corn plants.
Fall armyworm fact sheet [PDF, 833 KB]
Surveillance and research
As part of the work against FAW, Better Border Biosecurity (B3) has started a research programme. It's to better understand the survival, distribution, and potential impacts of this moth pest in New Zealand. From September 2022, more than 200 FAW pheromone traps will be distributed around the country to support the B3 research work.
How farmers and growers can help
To further support this B3 research, we'd like farmers and growers to keep a lookout for FAW on their properties over the spring and summer months. This includes growers who have deployed their own FAW pheromone traps, are undertaking crop scouting, or just making regular checks of their crops. Even if you do not detect FAW, we want you to tell us.
Moth surveillance is an important first action in management because it alerts growers of the presence of local fall armyworm activity.
Short field guide for identifying Fall armyworm [PDF, 653 KB]
Fall armyworm quick growers guide [PDF, 657 KB]
If you think you have detected FAW on your crops
- Take a clear dorsal (top down) photo – the caterpillars you photograph should be at least 2cm long.
- Freephone our pest and disease hotline (0800 80 99 66) or make a report online
Alternatively, you can report a detection using the Find-A-Pest app
Note that FAW can easily be mistaken for other species that are already in New Zealand.
Check 3 other species often confused with FAW
If you don't find any FAW on your property
We would still like to know about it to help build a picture of their distribution. Report no findings to us at the end of each month (between September 2022 and 31 March 2023) using the negative surveillance form.
Fall armyworm negative surveillance reporting form [DOCX, 686 KB]
Send completed forms to faw@mpi.govt.nz
About the fall armyworm
Fall armyworm is the name commonly attributed to the larval stage of the moth Spodoptera frugiperda.
The fall armyworm life cycle
- Egg stage.
- 6 caterpillar (larval) stages.
- A pupal stage.
- An adult moth stage.
The larval life cycle stages cause widespread damage to crops through feeding.
Fall armyworm eggs
- Usually laid on the under surface of leaves in clustered masses of 100 to 200.
- The masses are covered with a ‘felt like’ layer of scales.
- The eggs are pale yellow.
Fall armyworm larvae
- Small larvae are usually light green to brown, with a dark head capsule. Young larvae feed on one surface of the leaf.
- Large fall armyworm larvae grow to 3cm to 4cm, becoming darker as they mature, with pale white stripes along the length of the body.
- The large caterpillars have a pale inverted “Y” shape between the eyes. Two dark spots with dark spines occur on each body segment on the upper body surface, with 4 black spots arranged in a square on the second last abdominal segment.
- Larvae normally pupate in the soil. The pupae are shiny brown and between 1.3cm and 1.7cm long.
Adult fall armyworm moths
- Measure 3cm to 4cm from wingtip to wingtip.
- Female moths are slightly larger than males, although both sexes have a white hindwing with a dark-brown margin.
- Male moths are more patterned and have distinct triangular white spots at the tip and near the centre of each forewing.
Fall armyworm identification sheet [PDF, 1.5 MB]
Images of the fall armyworm
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Risk to New Zealand
Fall armyworm larvae feed on more than 350 plant species, especially sweetcorn and maize.
Adult fall armyworm moths are strong flyers and will travel hundreds of kilometres on storm fronts. The larvae can also be spread in cut flower, fruit and vegetable consignments.
This moth has been on our radar for some time, as it has been spreading around the world. It is present in the Americas, Africa and Asia, and is established in parts of Australia.
Our risk analysis found it would struggle to establish here as areas with preferred hosts do not necessarily have the correct climate to suit fall armyworm.
Similar species to the fall armyworm
Particularly in the larval stage, fall armyworm can often be mistaken for closely related species. The most mistaken larvae are the:
- Cosmopolitan armyworm (Mythimna separata)
- Tropical armyworm (Spodoptera litura)
- Corn earworm (Helicoverpa armigera).
All 3 species are found throughout the North Island. Know how to spot the difference.
