Keep watch: fall armyworm has started marching

9 November 2026

As the weather continues to warm up, farmers are encouraged to up-skill on how to correctly identify Fall armyworm in their crops.

Agriculture Victoria horticulture program coordinator for Gippsland Scott Botten said native armyworms can often be mistaken for fall armyworm (FAW).

‘FAW are native to tropical and subtropical regions of the Americas but have quickly spread across the world.

‘The fall armyworm, also known as Spodoptera frugiperda, is a highly invasive and destructive caterpillar that poses a significant threat to plant species.

‘They are known to feed on more than 350 plant species, including maize, cotton, rice, sorghum, sugarcane, wheat and other vegetable and fruit crops.

‘Young caterpillars feed on leaves, creating pinholes and giving a tattered appearance.

‘The mature caterpillars can cause extensive damage by grazing on leaf stems and trunks and tunnelling into fruit.’

Mr Botten said while having a similar appearance to other armyworm species commonly found in Victoria, when identifying FAW there are several key signs to look for:

• An inverted Y shape on the head.
• Mature caterpillars are smooth bodied and grow up to 40 mm in length.
• They range in colour from dark yellow to green, brown and black with prominent lighter stripes running the length of the body.
• Eggs are laid on the underside of leaves in masses of 100 to 300, usually with a protective cover of fine bristles.
• Newly hatched larvae (caterpillars) are 1 mm long, pale greenish with a black head.
• Males have 2 distinct white marks on each of the forewings.

‘Correctly identifying FAW is especially vital during late summer, when the larvae are most active.

‘If you think you have identified a FAW and aren’t sure of next steps, contact your local agronomist for advice,’ he said.

Further information on fall armyworm, including monitoring and how to identify it can be found on Fall Armyworm webpage.

Media contact: Makayla Rimington

Phone: 0473 914 662