Fall armyworm

Adults

• Moth, 15–20mm with a 32–40mm wingspan.
• Brown or grey forewing and a white hind wing.
• Male fall armyworm moths have more patterns and a distinct white spot on each forewing.

Larvae

• When larvae are newly hatched they are about 1.7mm, light green to brown with a larger, darker head.
• As they develop, they become a darker greyish-brown with white lengthwise stripes and dark spots with spines on their upper surface, with a pale underside. Older larvae have a distinctive pattern of 4 spots on the second to last body segment and an inverted 'Y' shape pattern on their heads.
• Eventually reach a length of about 34mm.

Pupae

• The pupa is red-brown, 14–18mm long and approximately 4.5mm wide. Pupation mostly occurs in the soil under the host plant, occasionally in host vegetation.

Egg

• Pale yellow and clustered together in a mass.
• An egg mass can contain 100–200 eggs.
• Egg masses are usually attached to foliage in a mound, with a silk-like furry substance.

Plant stage and plant parts affected

The larvae can affect leaves, shoots, stems and fruit. Plants of different ages, from seedlings to mature plants, can be affected.

Plant damage

Fall armyworm larvae initially feed on leaves, creating pinholes and windows in leaf tissue, and giving leaf margins a tattered appearance. In grass-like plants, they often feed within the leaf whorl (where leaves radiate from or wrap around the stem or stalk—see image 2). Insect frass (droppings) is a sign that larvae are present.

Fall armyworm larvae can also eat buds and tunnel into and feed on fruit. Larger larvae can cut plants off at the base.

Many larvae may be present on 1 plant. When they are found in large numbers, they can defoliate preferred host plants and acquire an 'armyworm' habit and disperse in large numbers. Crops have been reportedly been destroyed almost overnight.

Identification and symptoms guide

Read our fall armyworm larvae ID guide.

Read about identifying cluster caterpillar, northern armyworm and fall armyworm (PDF, 652KB).

Fall armyworm can be confused with a number of armyworm species that are present in Australia. If in doubt, contact the Department of Agriculture and Fisheries on 13 25 23.

Fall armyworm is native to tropical and subtropical regions of the Americas. Since 2016 it has rapidly spread to and throughout Africa, the Indian subcontinent, China and Southeast Asia.

There are approximately 350 plant species hosts. These include economically important cultivated grasses such as maize, rice, sorghum, sugarcane and wheat but also other vegetable and fruit crops and cotton. View the full list of known hosts.

Watch a video about the fall armyworm lifecycle.

Fall armyworm poses a threat to Queensland's agricultural industries.

Damage caused by fall armyworm can reduce plant growth, significantly reduce crop yield and cause plant death. Severe infestations can destroy crops rapidly.

Since fall armyworm can also graze on some pasture species, our environment may also be impacted.

The adult moths are capable of flying long distances. In the Americas, adult moths can undertake annual seasonal migration as far north as Canada.

Fall armyworm can also spread through people movement. It is believed that the arrival of fall armyworm in Africa was on a passenger flight.

Fall armyworm can spread on the illegal importation or movement of infested plant material.

The Australian Government closely regulates approved imports of plant material and monitors for illegal plant movement.

Inspect your plants regularly for the presence of unusual pest and disease symptoms.

To help identify symptoms of fall armyworm, examine plants for:

• leaf damage, including pinholes, windowing, tattered leaf margins and defoliation of plants
• tiny larvae, less than 1mm, that are more active at night, eating pinholes and transparent windows in leaves
• bigger larvae grazing on leaves, stems, trunk and fruit, and leaving behind insect frass (droppings)
• in monocots, larvae are often in plant whorls (where leaves radiate from or wrap around the stem or stalk (see image 2)
• regular crop monitoring is essential to avoid undetected crops damage.

If you suspect fall armyworm, report immediately to the Department of Agriculture and Fisheries on 13 25 23.

Protect your farm from plant pests and diseases:

• Protect your farm from emergency plant pests
• Understand good farm biosecurity
• Visit the farm biosecurity website

If you suspect fall armyworm, phone 13 25 23 to seek advice on control options.

The Australian Department of Agriculture has import conditions in place for importing plants and plant products.