Mythimna convecta

Mythimna convecta (Walker, 1857)
(one synonym : Pseudaletia evansi)
Common Armyworm
HADENINAE , NOCTUIDAE

Don Herbison-Evans ( donherbisonevans@yahoo.com )
&
Stella Crossley

Mythimna convecta
(Photo: courtesy of the Macleay Museum, University of Sydney)

This Caterpillar is brown, with dashed black stripes along the back, and two wide pale stripes along the sides. The two dorsal stripes continue over the thorax and head. The head is also stippled in black and brown.

(Photo: courtesy of the Macleay Museum, University of Sydney)

It is an agricultural pest, causing damage to pastures and crops. It hides by day, and feeds nocturnally on many plants, including :

various Grasses and Cereals ( POACEAE ).

Pineapple ( Ananas comosus, BROMELIACEAE ),

Sweet Potato ( Ipomoea batatas, CONVOLVULACEAE ), and

Alfalfa ( Medicago sativa, FABACEAE ).

They are called 'Army Worms' because of their habit of spreading out in a line across a lawn or pasture, and marching across it (somewhat slowly) consuming the foliage as they go.

(Photo: courtesy of the Macleay Museum, University of Sydney)

The adult moth has forewings that are a speckled rusty brown, each with a white dot in the middle which is outlined in black.

The hind wings are buff with dark edges. It has a wingspan of about 4 cms.

(Specimen: courtesy of the The Australian Museum)

The species is migratory, and occurs across most of Australia, including

Australian Capital Territory,

Northern Territory,

Queensland,

South Australia,

Tasmania,

Victoria, and

Western Australia.

Attempts to control the pest include :

using a garden roller at midnight (when they are attacking a lawn),

digging post holes for the larvae to congregate in during the daytime, where they may be crushed,

laying some sacking near the plants attacked, so that the Caterpillars will hide under that by daytime, and they may be then collected and disposed of,

various chemical insecticides
(chlorpyrifos, alpha-cypermethrin, trichlorfon, carbaryl, methomyl)

a nuclear polyhedrosis virus,

the fungus Nomuraea rileyi,

the nematode Steinernema carpocapsae ( STEINERNEMATIDAE ),

a wasp Netelia species, ( ICHNEUMONIDAE ),

the wasp Apanteles ruficrus ( BRACHONIDAE ), and

various flies, including Ceromya horma ( TACHINIDAE ).