The dark sword-grass or black cutworm (Agrotis ipsilon ) is a small noctuid

Noctuidae

The Noctuidae or owlet moths are a family of robustly-built moths that includes more than 35,000 known species out of possibly 100,000 total, in more than 4,200 genera. They constitute the largest family in the Lepidoptera....

 moth

Moth

A moth is an insect closely related to the butterfly, both being of the order Lepidoptera. Moths form the majority of this order; there are thought to be 150,000 to 250,000 different species of moth , with thousands of species yet to be described...

 found worldwide. The larva is a serious agricultural pest and feeds on nearly all varieties of vegetables and many important grains.

Description

The dark sword-grass has pale brown forewings with dark brown and black markings and translucent hindwings, greyish white with brown venation. The hindwings have a thin dark line along the margins of the hindwings.
The moth gets its specific name from black markings on the forewings shaped like a Y and resembling the Greek letter 'ipsilon'.

The moth has a wingspan of from four to five and a half centimetres.

Range

The moth is found in many regions of the world. It is absent from some tropical regions and colder areas and is more widespread in the northern than the southern hemisphere. It reinvades temperate areas each year having overwintered in warmer or subtropical regions.

Life cycle

The caterpillar of the Dark Sword-grass is smooth and ranges from purplish to brown in colour and is patterned with grey lines and spots.

Host plants

The adults feed on nectar from flowers. Weeds are often preferred to crops by the larvae. Some favoured species include bluegrass, curled dock, lambsquarters

Chenopodium album

Chenopodium album is a fast-growing weedy annual plant in the genus Chenopodium.Though cultivated in some regions, the plant is elsewhere considered a weed...

, yellow rocket

Barbarea vulgaris

Barbarea vulgaris, also called as Bittercress, Herb Barbara, Rocketcress, Yellow Rocketcress, Winter Rocket, and Wound Rocket, is a biennial herb of the genus Barbarea, belonging to the family Brassicaceae....

 and redroot pigweed

Amaranthus retroflexus

Amaranthus retroflexus is a species of flowering plant in the Amaranthaceae family with several common names, including Red-root Amaranth, Redroot Pigweed, Red Rooted Pigweed, Common Amaranth, and common tumble weed....

. Among crop plants, the larvae favour most vegetable plants, alfalfa

Alfalfa

Alfalfa is a flowering plant in the pea family Fabaceae cultivated as an important forage crop in the US, Canada, Argentina, France, Australia, the Middle East, South Africa, and many other countries. It is known as lucerne in the UK, France, Australia, South Africa and New Zealand, and known as...

, clover

Clover

Clover , or trefoil, is a genus of about 300 species of plants in the leguminous pea family Fabaceae. The genus has a cosmopolitan distribution; the highest diversity is found in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes...

, cotton

Cotton

Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

, rice

Rice

Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...

, sorghum

Sorghum

Sorghum is a genus of numerous species of grasses, one of which is raised for grain and many of which are used as fodder plants either cultivated or as part of pasture. The plants are cultivated in warmer climates worldwide. Species are native to tropical and subtropical regions of all continents...

, strawberry, sugarbeet

Sugar beet

Sugar beet, a cultivated plant of Beta vulgaris, is a plant whose tuber contains a high concentration of sucrose. It is grown commercially for sugar production. Sugar beets and other B...

, tobacco

Tobacco

Tobacco is an agricultural product processed from the leaves of plants in the genus Nicotiana. It can be consumed, used as a pesticide and, in the form of nicotine tartrate, used in some medicines...

and sometimes grains and grasses.

Damage

Each larva can consume over 400 square centimetres of foliage during its development. They feed above ground until about the fourth instar. After that they do considerable damage to crops by severing young plants at ground level. In the midwestern USA the black cutworm is considered to be a serious pest of corn which is very susceptible at the one-leaf stage but by the 4 or 5-leaf stage it is relatively unaffected. Damage to the underground parts of plants can also be harmful. Other crops where serious damage occurs include cotton, maize, tobacco, sunflower, tomatoes, sugar beet and potato.

External links

• Herbison-Evans, Don; Crossley, Stella (2006) Agrotis ipsilon