Insect Science and its Application (2002) 22, 105-112
Joseph B. Ackonor (2002)
Current levels of incidence of parasitism and predation in Planococcus citri Risso (Homoptera: Pseudococcidae) in Ghanaian cocoa (Theobroma cacao L.) farms
Insect Science and its Application 22 (2), 105-112
Abstract: From August 1988 to January 1997, natural enemies were reared from 335 colonies of Planococcus citri Risso (Homoptera: Pseudococcidae) sampled for 87 months from 225 randomly selected cocoa farms in the six cocoa-growing regions in Ghana. A total of 20,408 P. citri individuals was recorded, comprising adult females, third instar nymphs and mummified individuals harbouring parasitoids. Observed predators were larvae of Coccodiplosis coffeae Barnes (Diptera: Cecidomyiidae), nymphs and adults of Hyperaspis egregia Mader and Scymnus (Pullus) sp. (Coleoptera: Coccinellidae), as well as an unidentified lepidopteran. Twelve parasitic Hymenoptera were also reared, including Aenasius abengourouii (Risbec), Leptomastix dactylopii Howard, Anagyrus beneficians Compere, Tropidophryne melvillei Compere, Anagyrus amoenus Compere and Chryptochetum (Lestophonus) spp. Also recorded were a hyperparasitoid, Cheiloneurus carinatus Compere, parasitising Coc. coffeae , Xyphigaster pseudococci Risbec and six rare, undetermined parasitoids. Coccodiplosis coffeae was the commonest parasitoid, occurring throughout the year and infesting 72.8% of the P. citri colonies. Parasitism levels were generally low, the highest mean being 4.6 ± 2.6% for Aen. abengouroui . Simultaneous parasitism by more than one species was common and this gave rise to mean monthly parasitism levels ranging from 0.8 to 4.5%. Aenasius abengourouii, Ana. amoenus and H. egregia are being reported for the first time in P. citri on cocoa in Ghana, and the recovery of L. dactylopii suggests its establishment in the country, where it was introduced in 1949.
Entre août 1988 et janvier 1997, nous avons élevé les ennemis naturels de 335 colonies de Planococcus citri échantillonnées pendant 87 mois dans 225 fermes de cacaoyers choisies au hazard au Ghana. Vingt milles, quatre cent-huit individus de P. citri ont été dénombrés, comprenant des adultes femelles, des larves de troisième stade, et des individus momifiés. Les prédateurs observés ont été des larves de Coccodiplosis coffeae Barnes (Diptera: Cecidomyiidae), des larves et des adultes d' Hyperaspis egregia Mader et Scymnus (Pullus) sp. (Coleoptera: Coccinellidae), ainsi que des Lépidoptères inconnus. Douze Hyménoptères parasitoïdes ont été élevées, comprenant Aenasius abengouroui (Risbec), Leptomastix dactylopii Howard, Anagyrus beneficians Compere, Tropidophryne melvillei Compere, Anagyrus amoenus Compere et Chryptochetum (Lestophonus) spp. On a observé aussi Cheiloneurus carinatus Compere, Xyphigaster pseudococci Risbec et six parasitoides inconnus. Coccodiplosis coffeae a été le plus commun, présent pendant toute l'année et infestant 72,8 % des colonies. Les niveaux de parasitisme ont été bas; le plus haut a été de 4,6 ± 2,6% chez Aen. abengouroui . Le multiparasitisme, causé par plus d'une espèce de parasitoide, a été commun, comprise entre 0,8 et 4,5 % de parasitisme moyen mensuel. Cet article est le premier à rapporter la présence de Aen. abengouroui , Ana. amoenus et H. egregia sur P. citri sur des cacaoyers au Ghana, ainsi que l'etablissement de L. dactylopii dans le pays, où il a été introduit en 1949.
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Database assignments for author(s): Joseph B. Ackonor
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
