Mythimna Unipuncta

Mythimna unipuncta

1. Common name and scientific name, Pictures under green tabs at the left.

2. Geographical distribution

M. unipuncta occurs in many countries. North and South America, England and South Europe.

3. Biological characteristics

The eggs are whitish, bead-like and are laid in masses. Caterpillars are smooth-bodied and have alternating light and dark stripes running lengthwise along the top and sides of the body. Young larvae have stripes on greenisgrey background while older larvae have stripes on a greenishbrown or black background. There is some variation in the coloration of stripes as larvae mature. Mature larvae have the following pattern of stripes: There is a narrow broken stripe down the centre of the back. This is bordered by a wider, darker, mottled one (half of this stripe reaches the side). Seen from the side there are three stripes of about equal width. Below the darker mottled stripe is 1) a pale-orange, white-bordered stripe, 2) a dark-brown, light-mottled stripe just reaching the spiracles, and 3) a pale-orange, unmottled one edged with white. The prolegs (false legs) at the posterior end of the caterpillar have a dark band on the outer side and a dark tip on the inner side. The pupa is red-brown and is approximately 2 cm long. Adults have a wingspan of 4 centimeters. Forewings are pale brown with a white dot near the centre. This dot is useful for identification. The hind wings are pale grey-brown and have a slightly darker area on the posterior edge. Larvae of the armyworm are often mistaken for that of the fall armyworm. On the armyworm, as mentioned above, at the top side of the caterpillar there is a wide dark (mottled) stripe above a lighter stripe. The fall armyworm has the opposite, a lighter stripe above a darker one, in this area. The fall armyworm also usually has an inverted white "Y" pattern on the front of the head.

4. Parts to be damaged

M. unipuncta attacks mainly grasses. Feeding of larvae and adults of the white speck can cause damage on the leaves.

5. Damage period

The larvae and adults feed almost during the night, therfore it's difficult to scout them. During the day if larvae are present, they often hide in the leaf whorl, in crop debris or under soil clods. Larvae are usually active for 3-4 weeks from late May to early July, depending on the weather conditions.

6. Economic impact

Economic impact is extremely low.

7. Investigation and monitoring system

Attacks can be monitored during field period, especially in the early morning or evening, when larvae and adults feed on plants.

8. Control methods

If larvae or adults are found, there are effective insecticides to control the moths.