Full Length Research Paper

Artificial infestations of Tapinanthus ogowensis (Engler) Danser (Loranthaceae) on three host species in the Logbessou Plateau (Douala, Cameroon)

Dibong Siegfried Didier¹*, Engone Obiang Nestor Laurier², Ndongo Din¹, Priso Richard Jules¹, Taffouo Victor¹, Fankem Henri¹, Salle Georges³ and Amougou Akoa⁴

¹Laboratoire d’ Ecologie végétale, Département de Biologie des Organismes végétaux, Faculté des Sciences, B. P. 24157, Université de Douala, Cameroun.

²Institut de Recherche d’Ecologie Tropicale (IRET), Libreville, Gabon.

³Laboratoire de Parasitologie végétale, Université Pierre et Marie Curie (Paris VI), 4 place Jussieu, case courrier 155, 75252 Paris Cedex 05, France.

⁴Département de Biologie et Physiologie Végétales, B. P. 812, Université de Yaoundé I, Cameroun.

*Corresponding author. E-mail: didierdibong@yahoo.fr.

Accepted 13 January, 2009

In Cameroon today, Loranthaceae has become a major pest against which a great “battle” must be launched if food production in the country has to be maintained at a self-sufficient level. However, an effective battle against pests can only be achieved through a better understanding of their geographical distribution and biology. Eight Loranthaceae species (Globimetula braunii, Globimetula dinklagei, Globimetula opaca, Helixanthera mannii, Phragmanthera capitata, Tapinanthus globiferus, Tapinanthus ogowensis, and Tapinanthus preussii) have been identified in the Douala area. Among these species, T. ogowensis is the only one limited to a surface area of about eight hectares in the Logbessou plateau located in a direction of North-East from Douala (Latitude 03°40 - 04°11' N, Longitude 09°16' - 09°52' E, and at an altitude of 13 m). In this zone, the hemi-parasite infests only one host tree (Dacryodes edulis) in the orchards, gardens and agricultural plantations. The hemiparasite is however common and adapted to all the different ecological regions in the southern part Cameroon where it infests several host trees. In order to study the stages involved in the germination, fixation, as well as the initial stages involved in the development of the seedlings of T. ogowensis, three of the most frequent host species (D. edulis, Mangifera indica and Persea americana) on the plateau were artificially infected. The results revealed that the host species are sensitive to the parasite, T. ogowensis, at least during their early stages of growth and development. D. edulis is the most sensitive host species with a 22% yield of young seedlings as against 5 and 4% for P. americana and M. indica, respectively. This sensitivity of the mango tree to T. ogowensis had never been demonstrated before. The percentages of seeds germinating on the different host species however remained high; 96% on both D. edulis and M. indica and 93% on P. americana. It was also revealed that the development of the young seedlings of T. ogowensis is greatly influenced by the availability of light, a plausible reason why Loranthaceae occupies mainly the uppermost branches of the oldest trees found here.

Key words: Artificial infestations, Cameroon, host species, Loranthaceae, Tapinanthus ogowensis.