Occurrence of African Mistletoe Erianthemum ulugurense on Toona ciliata and Other Trees in Kenya. M. E. Omunyin, Department of Plant Pathology, Iowa State University, Ames 50011 . M. N. Wabule, Kenya Agricultural Research Institute, Headquarters, P.O. Box 57811, Nairobi. Plant Dis. 80:823. Accepted for publication 6 May 1996. Copyright 1996 The American Phytopathological Society. DOI: 10.1094/PD-80-0823B.
Erianthemum ulugurense (Engl.) Danser (family: Loranthaceae), a parasitic flowering plant, was observed on trees at the National Horticultural Research Center located at Thika (1009' S 37°04' E, 1,549 m altitude) in Central Kenya. It was found in April 1984 growing as a shrub on trunks and branches of the Burma cedar, Toona ciliata M. Roemer (= Cedrela toona Roxb. ex Rottl. & Willd), an important hardwood in East Africa (I). Erianthemum ulugurense (specimen no. E A. 16976, East African Herbarium, Nairobi, Kenya) is characterized by the presence of thick green leaves, absence of a true root system, and production of light green to orange flowers. Several thick, erect stems may arise at the infection point of the host, which usually swells to form a tumor. During the rainy season (April to June) 1989, E. ulugurense was observed on other tree species, on which dieback of infected branches was observed. Occurrence of E. ulugurense was assessed in a 300-ha area in four quadrats, each 50 m x 50 m, and by observation of the parasite on tree trunks and branches. In addition to T. ciliata, the host range included Bauhinia monandra Kurz, Callistemon rigidus R. Br., Cassia siamea Lam., Ficus benjamina L. (benjamin fig), Jacaranda mimosifolia D. Don, Nerium oleander L. (ornamental oleander), Punica granatum L. (pomegranate), and Schinus molle L. When trees were compared for incidence of E. ulugurense, the mean count of individuals of the parasite per host was greater for T. ciliata than for F. benjamina, but did not differ among T. ciliata, B. monandra, and 5. molle, or among F. benjamina, N. oleander, and J. mimosifolia (P = 0.05). Incidence of the pathogen was 69% in the sampled area. Tree species on which no E. ulugurense were found included Acrocarpus fraxinifolius Am., Casuarina equisetifolia L., Cupres-sus arizonica E. Greene, and Grevillea robusta Cunn. Records of E. ulugurense at the East African Herbarium Index (Nairobi, Kenya) showed that it also attacks the black wattle tree Acacia mollissima Willd., Carissa edulis Vahl, Juniperus sp., Olea africana Mill., Prunus spp., and Rhus natalensis Bernh. ex Krauss; thus, we observed E. ulugurense on a broadened host range. This is the first report of the parasite at Thika in Kenya. A country-wide survey and program is needed to study the biology and control of this serious pathogen.Reference: (I) F. M. L. Sheffield et al. East Afr. Agric. For. J. 30:345, 1965.