''Diparopsis castanea'' is the type species of the genus '' Diparopsis'': moths in the family

Noctuidae The Noctuidae, commonly known as owlet moths, cutworms or armyworms, are a family of moths. They are considered the most controversial family in the superfamily Noctuoidea because many of the clades are constantly changing, along with the other f ...

; no subspecies are listed in the

Catalogue of Life The Catalogue of Life is an online database that provides an index of known species of animals, plants, fungi, and microorganisms. It was created in 2001 as a partnership between the global Species 2000 and the American Integrated Taxonomic Info ...

. This is known as the red

bollworm Bollworm is the common term for a moth larva that attacks the fruiting bodies of certain crops, especially cotton. The most common moths known as bollworms are: * Red or Sudan bollworm, '' Diparopsis castanea'' * Rough bollworm, '' Earias perhuege ...

, which is a significant pest of

cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus ''Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor perce ...

crops in Eastern and Central-Southern Africa.

Host Plants and Life cycle

''Diparopsis castanea'' is

oligophagous Oligophagy refers to the eating of only a few specific foods, and to monophagy when restricted to a single food source. The term is usually associated with insect dietary behaviour.Gossypium ''Gossypium'' () is a genus of flowering plants in the tribe Gossypieae of the mallow family, Malvaceae, from which cotton is harvested. It is native to tropical and subtropical regions of the Old and New Worlds. There are about 50 ''Gossypiu ...

'' spp.), and a rare wild host plant: ''

Cienfuegosia ''Cienfuegosia'' is a genus of plants, in the family Malvaceae and placed in the tribe Gossypieae Gossypieae is a tribe of the flowering plant subfamily Malvoideae. It includes the cotton (''Gossypium'') and related plants. It is distinguished ...

hildebrandtii'' (also in the tribe

Gossypieae Gossypieae is a tribe of the flowering plant subfamily Malvoideae. It includes the cotton (''Gossypium'') and related plants. It is distinguished from the Hibisceae on the basis of embryo structure and its apparently unique possession of glands a ...

). The sky blue eggs are laid singly on stems leaves and

bract In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...

s and hatch in to larvae that rapidly seek out and penetrate seed capsules (''i.e.'' bolls). The most effective chemical treatments against this pest include sprays that are directed against the eggs and first

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

, because after this stage the larvae remain inside the bolls. The main infestation occurs during mid to late crop stage, and as the pupae can undergo diapause, the pest readily survives the dry season. File:First instar RBW on cotton bud.jpg, First instar on cotton bud File:Red Bollworm larva in a boll.jpg File:Diparopsis moth emerging.jpg, ''Diparopsis'' moth emerging File:Diparopsis moth just after emergence.jpg

Pest Status and Management

Integrated pest management Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad-based approach that integrates both chemical and non-chemical practices for economic control of pests. IPM aims to suppress pest populations below the econ ...

includes implementation of a

close season In an organized sports league, a typical season is the portion of one year in which regulated games of the sport are in session: for example, in Major League Baseball the season lasts approximately from the last week of March to the last week of Se ...

, during which farmers' fields must be cleared of all cotton plant material for at least two months; this has been mandatory in Zimbabwe since the 1930s and in Malawi since 1965. In the presence of a continuous supply of food plant material populations can increase and cause severe crop loss. Low level, persistent infestations represented by 1 egg observed for every 10 plants may cause significant losses; in Zimbabwe, the normal threshold is 6 eggs on 24 plants. Monitoring recommendations involve accumulating numbers of eggs over two or three consecutive counts. Diparopsis is readily controlled by well-timed insecticide applications. Originally, chemicals such as

DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...

and

carbaryl Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid previously sold under the brand name Sevin, which was a trademark of the Bayer Company. The Sevin tradem ...

were recommended, but since the 1980s chemicals have included the

pyrethroid A pyrethroid is an organic compound similar to the natural pyrethrins, which are produced by the flowers of pyrethrums (''Chrysanthemum cinerariaefolium'' and ''Chrysanthemum coccineum, C. coccineum''). Pyrethroids are used as commercial and hou ...

insecticides. The eggs are more evenly distributed throughout the plant than ''

Helicoverpa ''Helicoverpa'' is a genus of moths in the family Noctuidae first described by David F. Hardwick in 1965. Some species are among the worst Lepidopteran agricultural pests in the world, and three species (''H. armigera'', ''H. zea'', and ''H. pu ...

'' bollworms, so

spray Spray or spraying commonly refer to: * Spray (liquid drop) ** Aerosol spray ** Blood spray ** Hair spray ** Nasal spray ** Pepper spray ** PAVA spray ** Road spray or tire spray, road debris kicked up from a vehicle tire ** Sea spray, refers to ...

penetration is more important for effective treatment.Matthews GA, Mowlam MD (1974) Some Aspects of the Biology of Cotton Insects and their Control with U.L.V. Spraying in Malawi. ''British Crop Protection Council Monograph'' No. 11 pp. 44-52.

References

External links

Natural History Museum Lepidoptera genus database
{{Taxonbar, from=Q13510352 Hadeninae Insects of Africa Agricultural pest insects