Can you confidently identify armyworm and helicoverpa larvae in winter cereals?

Both Helicoverpa armigera and armyworm larvae are occurring together in wheat and barley. It is important to be able to separate the helicoverpa larvae from the armyworm larvae in order to determine whether the numbers are above or below threshold, and, if needed, to make the most appropriate decision about control options.

Armyworm larvae

• have three white stripes on the collar, behind the head. These stripes may or may not persist down the body so concentrate on the collar (see the image above at right).
• skin is smooth without obvious hairs and bumps.
• larger larvae tend to curl up when disturbed.

Helicoverpa larvae

• skin is lumpy with obvious hairs.
• may be considerable variation in colour.
• may or may not have a ’saddle’.