Fall Armyworm Management in Maize and Sweetcorn

Is it Fall armyworm?

There are three key characteristics used in combination that will help identify FAW. First, a distinct ‘Y’ on the head leading into the dorsal line. Second, four trapezoid patterned dots on the body segments. Finally, four pronounced dots in a square pattern at the rear. Other pests may share a similar identification but not all three key markings together.

Should I be monitoring my crop?

Crop monitoring is vital for managing pests in maize and sweetcorn effectively. Regular monitoring starts as soon as crops are planted. The most effective crop monitoring tool is crop scouting, which is defined as 'careful continuous observation', where a crop scout walks the whole crop to assess infestations and fresh damage.

How do I monitor my crop?

1. Identify the crop stage and plan the scouting choose a pattern (zig-zag or "W" shape) to cover all parts of the field. 2. Walk the field properly follow the planned path, and stop at regular points across the field. 3.

Why does the size of the caterpillar matter?

Identifying the size of Fall armyworm (FAW) larvae is important for effective targeted chemical intervention because smaller larvae are more vulnerable to insecticides. Early detection of young larvae, typically less than 10 mm in length, allows for more effective control before they burrow into the whorl or cob.

What are other similar pests in maize?

Helicoverpa armigera (Corn earworm) Helicoverpa armigera is a significant maize and sweetcorn pest in New Zealand. The Corn earworm at the top shows a hairy and diamond-like pattern, it looks spikey in comparison to the FAW larvae below, which also clearly shows 4 pronounced dots in a square shape at its rear. Helicoverpa armigera can vary in colour, appearing green, yellow, black, and even pink.