Biosecurity alert - Fall Armyworm

13 Dec 2021

Farmers are being urged to look out for fall armyworm (FAW) in crops after the insect pest was recently detected in NSW.

The insect pest is a serious threat to a wide range of industries. It can attack a wide range of crops but maize, sorghum and cotton are favoured hosts.

Moths and small larvae are quite difficult to identify although the small larva have a dark head capsule. Larger larvae have a distinctive ‘Y” pattern on the head capsule and four dark spots arranged in a square pattern to rear of the body. Each body segment has two dark spots with spines. Eggs are laid on the underside of leaves in a mass that has a felt like appearance.

In northern Australia the pest will survive year-round however in NSW FAW will likely be seasonal pest during spring summer and autumn. Moths can travel large distances and migrations from northern Australia to southern Australia are likely to occur each year. Growers are advised to monitor summer crops.

Symptoms include eggs on the underside of the lower leaf, “windowing” of leaves and “shot holes” in leaves, in particular the plant whorl from where new leaves emerge should be inspected.

Fall Armyworm fast facts

Seasonal migratory pest in most NSW regions
Development is highly temperature dependant
24-55 day life cycle (egg to adult)
Pupae cannot diapause in response to low temperatures
Pheromone traps alert growers to seasonal activity attracting adult male moths

The host range of FAW includes more than 140 species of reported cultivated and wild plants within the Poaceae (grasses) family and non-grass hosts. While Australian research is ongoing, recent international research indicates that Fall Armyworm tends to favour summer crops in this general order.

What you need to know when managing Fall Armyworm

Regularly monitor your crops
Do not spray unnecessarily, only spray when economic thresholds are reached. You can find information about economic thresholds in this Plant Health Australia resource.
Comply with label instructions to avoid prophylactic spraying
Timely application of selective insecticides where possible
Rotate chemicals with different MoA
Consider the use of biological options such as BT and virus products
Report all suspect fall armyworm sightings.

Notifiable plant pest

Fall Armyworm is a notifiable plant pest in NSW. All notifiable plant pests and diseases must be reported within one working day. Report notifiable plant pests and diseases: