<P> The cotton bollworm, corn earworm, or Old World (African) bollworm (Helicoverpa armigera) (also known as the scarce bordered straw in the UK, where it is a migrant) is a moth, the larvae of which feed on a wide range of plants, including many important cultivated crops . It is a major pest in cotton and one of the most polyphagous and cosmopolitan pest species . It should not be confused with the similarly named, related species Helicoverpa zea . </P> <P> This species comprises two sub-species: Helicoverpa armigera armigera is widespread in central and southern Europe, temperate Asia and Africa; Helicoverpa armigera conferta is found in Australia, and Oceania . The former sub-species has also recently been confirmed to have successfully invaded Brazil and has since spread across much of South America and reached the Caribbean . It is a migrant species, able to reach Scandinavia and other northern territories . </P> <P> The cotton bollworm is very variable in both size and colour . The body length varies between 12 and 20 millimetres (0.47 and 0.79 in) with a wingspan of 30--40 millimetres (1.2--1.6 in). The fore wings are yellowish to orange in females and greenish - gray in males, with a slightly darker transversal band in the distal third . The external transversal and submarginal lines and the reniform spot are diffused . The hind wings are a pale yellow with a narrow brown band at the external edge and a dark round spot in the middle . </P> <P> The female cotton bollworm can lay several hundred eggs, distributed on various parts of the plant . Under favourable conditions, the eggs can hatch into larvae within three days and the whole lifecycle can be completed in just over a month . </P>

Identifying features and economic importance of helicoverpa armigera