Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2025-01-03T14:05:27.240Z Has data issue: false hasContentIssue false
  • English
  • Français

The biology of Earias biplaga Wlk. (Lep., Noctuidae) on Theobroma cacao in Western Nigeria

Published online by Cambridge University Press:  10 July 2009

P. F. Entwistle
P. F. Entwistle
Affiliation:
Insect Pathology Unit, Commonwealth Forestry Institute, University of Oxford
Get access Rights & Permissions [Opens in a new window]

Extract

Earias biplaga Wlk. has been recorded to attack Theobroma cacao from the Ivory Coast to the Congo (Léopoldville) and also in San Thomé and is the only species of the genus to do so in Africa. Attack is most serious on seedlings in the field as the apical buds are destroyed.

Eggs are laid on the stem mainly, especially on leaf bracts. The first half of the larval period is passed within the apical bud and the last half in feeding on unhardened flush leaves, or, in their absence, in burrowing down the stem below the apex or in devouring the epidermis of the upper stem.

The length of the larval and pupal periods is inversely related to the mean maximum temperature; they are shortest in the dry season and longest in the wet season.

Differences between the sexes exist in the wing coloration, and in the shape of the labial palps, the last segment of which is much longer in the female than in the male. The dry-season form, which has the forewings suffused with golden brown in the female and with yellow-green in the male, instead of the wet-season green, occurs from January to March in the region of Ibadan, Western Nigeria.

The adults are largely nocturnal and they are attracted to ultra-violet light.

Adults lived longer in the laboratory on a diet of sucrose in water (males, on average, 17 days and females, 28 days) than on water alone or without either. A mean of 95 eggs per female was recorded from sucrose-fed adults in the laboratory and the greatest number of eggs laid by a single female was 461. The peak period of oviposition was the fourth to fifth day after mating (fifth to sixth after emergence). A method of rearing E. biplaga in the laboratory is described.

Six alternative host-plants in Nigeria, all in the Malvales, are listed, and one, Hibiscus esculentus, is a locally important food crop. Nine Hymenopterous parasites were found to attack E. biplaga in Western Nigeria, the most important being Trichogramma luteum (Gir.) which attacks the eggs, destroying over 90 per cent, of them at certain times of the year. All the other parasites, with one possible exception, appeared to attack only the larval stage of the host.

Type
Research Paper
Information
Bulletin of Entomological Research , Volume 58 , Issue 3 , February 1969 , pp. 521 - 536
Copyright
Copyright © Cambridge University Press 1969

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ahmad, T. & Ghulamullah. (1939). Ecological studies on the spotted bollworms of cotton and their parasites. I. Indian J. Ent. 1 pp. 17–47.Google Scholar
Ahmad, T. & Ghulamullah. (1941). Ecological studies on the spotted bollworms of cotton and their parasites. II. Indian J. Ent. 3 pp. 245–284.Google Scholar
Alibert, H. (1951). Les insects vivant sur les cacaoyers en Afrique Occidentale.—Mém. Inst. franqç Afr. noire. no. 15, 174 pp.Google Scholar
Buyckx, E. J. E. (1962). Précis des maladies et des insects nuisibles rencontrés sur les plantes cultivées au Congo, au Rwanda et au Burundi.—Publ. Inst. natn. Etud. agron. Congo. hors sér., 708 pp.Google Scholar
Cotterell, G. S. (1928). Minor pests of cacao.—Bull. Dep. Agric. Gold Cst. no. 13 1927 pp. 100–106.Google Scholar
Deshpande, B. P., & Nadkarny, N. T. (1936). The spotted boll-worms of cotton (Earias fabia Stoll. and Earias insulana Boisd.) in Southern Gujarat, Bombay Presidency.—Scient. Monogr. imp. Coun. agric. Res. India. no. 10, 208 pp.Google Scholar
Entwistle, P. F. (1963). Earias biplaga.—Rep. W. Afr. Cocoa Res. Inst. 1961–1962. pp. 103–109.Google Scholar
Entwistle, P. F. (1964). Earias biplaga.—Rep. W. Afr. Cocoa Res. Inst. (Nigeria). 1962–63 pp. 49–55.Google Scholar
Entwistle, P. F. [1965]. Earias biplaga.—Rep. W. Afr. Cocoa Res. Inst. (Nigeria). 1963–1964 pp. 66–69.Google Scholar
Gerard, B. M. (1964). Insects associated with unshaded Theobroma cacao L. in Ghana.—Proc. Conf. Mirids & other pests of Cacao. pp. 101–111.Google Scholar
GhesquiÉre, J. (1923). Quelques ennemis du cacaoyer dans l’ouest african—Revue Bot. appl. Agric. trop. 3 pp. 117–120.Google Scholar
Golding, F. D. (1946). The insect pests of Nigerian crops and stock.—Spec. Bull. agric. Dep. Nigeria no. 4, 48 pp.Google Scholar
Hargreaves, E. (1937). Some insect pests and their food-plants in Sierra Leone.—Bull. ent. Res. 28, pp. 505–520.Google Scholar
Mallamaire, A. (1936). Rapports annuels du Laboratoire d’ Entomologie de Bingerville.Google Scholar
MaynÉ, R. (1917). Insects et autres animaux attaquant le cacaoyer au Congo Belge.—Etud. Biol. agric. no. 3, 80 pp.Google Scholar
Patterson, W. H. (1923). Notes on some of our cocoa pests.—J. Gold Cst agric. comml Soc. 2 pp. 95–102.Google Scholar
Pearson, E. O. (1958). The insect pests of cotton in tropical Africa.—355 pp. London, Emp. Cotton Grow. Corp. & Commonw. Inst. Ent.Google Scholar
Pomeroy, A. W. J. (1925). The cotton boll worms of Southern Nigeria.—4th A. Bull. Dep. Agric. Nigeria. pp. 89–108.Google Scholar
Smith, M. R. (1962). Minor pests.—Rep. W. Afr. Cocoa Res. Inst. 1960–1961 pp. 44–51.Google Scholar
Szent-Ivany, J. J. H. (1961). Insect pests of Theobroma cacao in the Territory of Pupua and New Guinea.—Papua New Guin. agric. J. 13 pp. 127–147.Google Scholar
Teissier, G. (1936). Livre loi de Dyar et la croissance des arthropodes.—In Bouvier, E. L., Livre jubilaire pp. 335–342. Paris, Firmin-Didot.Google Scholar
Willcocks, F. C. (1916). The insect and related pests of Egypt. Vol. 1. Pt. 1.—339 pp. Cairo, Sultanic Agric. Soc.Google Scholar