Latin name: Spodoptera
Armyworms are caterpillar pests of grass pastures and cereal crops.
They are the only caterpillars that growers are likely to encounter in cereal crops, although occasionally native budworm will also attack grain when underlying weed hosts dry out.
Armyworms mostly feed on leaves, but under certain circumstances will feed on the seed stem, resulting in head loss. The change in feeding habit is caused by depletion of green leaf material or crowding. In the unusual event of extreme food depletion and crowding, they will 'march' out of crops and pastures in search of food, which gives them the name 'armyworm'.
Distinguishing armyworm larvae from other pests
Armyworms can be distinguished from other caterpillar pests that may be found in the same place by 3 pale stripes that run the length of the body. These stay constant no matter what variation in the colour of the body.
Other species of caterpillar that might be confused with armyworms include the following:
- Loopers (tobacco looper or brown pasture looper) walk with a distinct looping action and have 1 or 2 pairs of abdominal prolegs — armyworms have 4 pairs, and when longer than 10mm, do not walk with a looping action.
- Budworm larvae have prominent but sparse hairs and bumps on their skin and anthelid larvae are covered in hairs — armyworms are smooth-bodied with no obvious hairs.
- Cabbage moth larvae wriggle vigorously when disturbed — armyworms curl up into a tight 'C'.
- Cutworm (brown or common cutworm) larvae have no obvious stripes or markings and are uniformly brown, pink or black.
SOLUTIONS:
- Contact: Proforce Rumbler 100SC, Apparent Surround
Armyworm photo courtesy of Indigo Specialty
