Larvae of both species are up to 40mm long with considerable colour variation (usually shades of brown, green and orange) and have lines and bands running along the length of the body. The body is sparsely covered with small bumps and bristles and long stiff black hairs. Newly hatched larvae are light in colour with tiny dark spots and dark heads. As  larvae develop they become darker in colour and the darker spots become more obvious. Both species of Helicoverpa have four pairs of abdominal prolegs in addition to a pair of anal prolegs.

It is possible to distinguish between Helicoverpa species for medium and large larvae, pupae and adults. H.armigera have white hairs around the head, medium larvae have a saddle of darker pigment on the fourth abdominal segment (see photo) and dark coloured legs.

Size categories

• Large (23mm plus)
• Medium (7-23mm)
• Small (3-7mm)
• Very small (1.5-3mm)

Note: false legs, size and colour variation in caterpillars.

H.punctigera have black hairs around the head (see photo), medium larvae have no saddle and light coloured legs.

Moths with a wing span of 30mm, forewings are buff olive to red brown with dark spots and blotches near the edge. H.punctigera are pale with a uniform dark band along the lower edge of the hindwing, while H.armigera have a small light or pale patch in the dark band.

Eggs

The eggs are 0.5mm in diameter and change colours from white when laid, to brown and then to a black before hatching. H.punctigera is more common in the southern region than H.armigera.