Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-11-28T12:23:17.187Z Has data issue: false hasContentIssue false
  • English
  • Français

MELANIZATION OF EGGS AND LARVAE OF THE PARASITOID, EPIDINOCARSIS LOPEZI (DE SANTIS) (HYMENOPTERA: ENCYRTIDAE), BY THE CASSAVA MEALYBUG, PHENACOCCUS MANIHOTI MATILE-FERRERO (HOMOPTERA: PSEUDOCOCCIDAE)

Published online by Cambridge University Press:  31 May 2012

Daniel J. Sullivan  and
Peter Neuenschwander
Daniel J. Sullivan
Affiliation:
Department of Biological Sciences, Fordham University, Bronx, New York, USA10458
Peter Neuenschwander
Affiliation:
International Institute of Tropical Agriculture (IITA), Ibadan, Nigeria
Get access Rights & Permissions [Opens in a new window]

Abstract

The encyrtid wasp Epidinocarsis lopezi (De Santis) has been introduced into Africa as a biological control agent against the cassava mealybug Phenacoccus manihoti Matile-Ferrero. This host has a defense reaction against the immature parasitoid that involves encapsulation and melanization. Under laboratory conditions, 37.5% of once-stung cassava mealybugs had been parasitized, as indicated by eggs and larvae of the parasitoid in dissected hosts. Of these parasitized cassava mealybugs, 89.6% contained melanized particles (egg, partially melanized larva, internal host tissues, exoskeleton wound scars). Some of the parasitoid larvae were only partially melanized, and either freed themselves from the melanized capsule or else shed it at the next molt. By the 3rd day of their development only 12.5% were completely melanized. In cassava mealybugs with melanized host tissue but no living parasitoid, the survival of the host was not affected by the melanization. The mealybug itself sometimes shed black particles at the next molt and these were found attached to the cast skins. When superparasitized in the laboratory, 68.6% of twice-stung cassava mealybugs contained parasitoids. Mummies collected from a field experiment showed that melanization rates of mummies increased with increasing parasitization rates. Thus, melanization in the cassava mealybug was commonly triggered when E. lopezi oviposited, but this defense reaction was mostly ineffective, permitting the introduced parasitoid to be a successful biological control agent in Africa against the cassava mealybug, a major pest on this important food crop.

Résumé

La guêpe encyrtide Epidinocarsis lopezi (De Santis) a été introduite en Afrique comme agent biologique de répression de la cochenille du cassava Phenacoccus manihoti Matile-Ferrero. L’hôte fait une réaction de défense caractérisée par l’encapsulation et la mélanization du parasitoïde immature. Dans des conditions de laboratoire, 37,5% des cochenilles attaquées une seule fois étaient effectivement parasitées, tel qu’établi par la présence d’oeufs et de larves à la dissection. Parmi ces cochenilles parasitées, 89,6% contenaient des particules mélanisées (oeufs, larves partiellement mélanisées, tissus internes de l’hôte, cicatrices exosquelettiques). Certaines des larves du parasitoïdes étaient mélanisées seulement en partie, et se sont libérées elles-mêmes de la capsule mélanisée ou l’ont rejetée lors de la mue suivante. Au troisième jour du développement de ces larves, seulement 12,5% étaient entièrement mélanisées. La survie des cochenilles montrant des tissus mélanisés en l’absence d’un parasitoïde vivant n’était pas affectée par la mélanisation. La cochenille elle-même rejetait parfois des particules noires avec l’exuvie lors de la mue suivante. Parmi les cochenilles superparasitées suite à deux attaques au laboratoire, 68,6%, contenaient des parasitoïdes. La collection de momies sur le terrain a montré une augmentation de l’incidence de mélanisation des momies avec l’augmentation de l’incidence du parasitisme. Ainsi, la mélanisation est fréquente chez les cochenilles recevant des oeufs d’E. lopezi, mais cette réaction de défense est plutôt inefficace, permettant à cet agent biologique introduit en Afrique d’agir avec succès contre la cochenille du cassava, un ravageur primaire de cette culture importante comme ressource alimentaire.

Type
Articles
Information
The Canadian Entomologist , Volume 120 , Issue 1 , January 1988 , pp. 63 - 71
Copyright
Copyright © Entomological Society of Canada 1988

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

Bess, H.A. 1939. Investigations on the resistance of mealybugs (Homoptera) to parasitization by internal hymenopterous parasites, with special reference to phagocytosis. Ann. ent. Soc. Am. 32: 189–226.CrossRefGoogle Scholar
Hammond, W.N.O., Neuenschwander, P., and Herren, H.R.. 1987. Impact of the exotic parasitoid Epidinocarsis lopezi on cassava mealybug (Phenacoccus manihoti) populations. In Neuenschwander, P., Yaninek, J.S., and Herren, H.R. (Eds.), Africa-wide Biological Control Project of Cassava Pests. Insect Sci. Applic. [Special Issue]. In press.Google Scholar
Herren, H.R., Neuenschwander, P., Hennessey, R.D., and Hammond, W.N.O.. 1987. Introduction and dispersal of Epidinocarsis lopezi (Hymenoptera: Encyrtidae), an exotic parasitoid of the cassava mealybug Phenacoccus manihoti (Homoptera: Pseudococcidae), in Africa. Agric. Ecosyst. Environ. In press.Google Scholar
Iziquel, Y. 1985. Le parasitisme de la cochenille du manioc Phenacoccus manihoti par l'Encyrtidae Apoanagyrus ( = Epidinocarsis) lopezi: induction, modalités, et conséquences agronomiques. Thèse, Université Rennes. 28 pp.Google Scholar
Kraaijeveld, A.R., and van Alphen, J.J.M.. 1986. Host-stage selection and sex allocation by Epidinocarsis lopezi (Hymenoptera: Encyrtidae), a parasitoid of the cassava mealybug, Phenacoccus manihoti (Homoptera: Pseudococcidae). Med. Fac. Landbouww. Rijksuniv. Gent. 51(3a): 1067–1078.Google Scholar
Neuenschwander, P., Haug, T., Herren, H.R., and Madojemu, E.. 1984. Improvement of the insectary. pp. 115–118 in IITA Annual Report for 1983. Int. Inst. Trop. Agric., Ibadan, Nigeria. 218 pp.Google Scholar
Neuenschwander, P., and Herren, H.R.. 1987. Biological control of the cassava mealybug, Phenacoccus manihoti, by the exotic parasitoid Epidinocarsis lopezi, in Africa. Phil. Trans. R. Soc. Lond. B. In press.Google Scholar
Neuenschwander, P., and Madojemu, E.. 1986. Mortality of the cassava mealybug, Phenacoccus manihoti. Mat.- Ferr. (Homoptera: Pseudococcidae), associated with an attack by Epidinocarsis lopezi (Hymenoptera: Encyrtidae). Mitt. Schweiz. Ent. Ges. 59: 57–62.Google Scholar
Neuenschwander, P., Schulthess, F., and Madojemu, E.. 1986. Experimental evaluation of the efficiency of Epidinocarsis lopezi, a parasitoid introduced into Africa against the cassava mealybug, Phenacoccus manihoti. Ent. Exp. Appl. 42: 133–138.CrossRefGoogle Scholar
Neuenschwander, P., and Sullivan, D.J.. 1987. Interactions between the endophagous parasitoid Epidinocarsis lopezi and its host, Phenacoccus manihoti. In Neuenschwander, P., Yaninek, J.S., and Herren, H.R. (Eds.), Africa-wide Biological Control Project of Cassava Pests. Insect Sci. Applic. [Special Issue]. In press.Google Scholar
Salt, G. 1956. Experimental studies in insect parasitism. IX. The reactions of a stick insect to an alien parasite. Proc. R. Soc. B. 144: 380–398.Google Scholar
Salt, G. 1970. The Cellular Defence Reactions of Insects. Cambridge Univ. Press, London. 118 pp.CrossRefGoogle Scholar
Sullivan, D.J., and Neuenschwander, P.. 1985. Melanization: the mealybug defends itself. pp. 127–129 in IITA Annual Report for 1984. Int. Inst. Trop. Agric., Ibadan, Nigeria. 238 pp.Google Scholar
van den Bosch, R. 1964. Encapsulation of the eggs of Bathyplectes curculionis (Thompson) (Hymenoptera: Ichneumonidae) in larvae of Hypera brunneipennis (Boheman) and Hypera postica (Gyllenhal) (Coleoptera: Curculionidae). J. Insect. Pathol. 6: 343–367.Google Scholar
Van Driesche, R.G., Bellotti, A., Herrera, C.J., and Castillo, J.A.. 1986. Encapsulation rates of two encyrtid parasitoids by two Phenacoccus spp. of cassava mealybugs in Colombia. Ent. Exp. Appl. 42: 79–82.CrossRefGoogle Scholar
Whitcomb, R.F., Shapiro, M., and Granados, R.R.. 1974. Insect defense mechanisms against microorganisms and parasitoids. pp. 447–536in Rockstein, M. (Ed.), Physiology of Insecta, Vol. 5. Academic Press, New York.CrossRefGoogle Scholar