Diseases of Plantation Forestry Trees in Southern Ghana

Ghana is on the verge of exhausting its timber resources and has embarked on reforestation. However, the establishment of pure stands of high value indigenous tree species such as Odum (Milicia excelsa and M. regia), Mahogany (Khaya and Entandrophragma species) and Kokrodua (Pericopsis elata) were not successful as a result of insect pest and disease problems. These failures, together with the need to establish plantations partly account for the widespread planting of teak (Tectona grandis), cedrela (Cedrela odorata) and other introduced tree species. Disease outbreaks in Tectona grandis, Cedrela odorata and Ceiba pentandra have been observed with the expansion of plantation estates. A study was therefore conducted to identify key diseases occurring in tree plantations, determine their distribution and evaluate management strategies to contain them. Diseases encountered include root rot caused by Armillaria hemii on T. grandis and Cedrela odorata, leaf spot and dieback on Ceiba pentandra seedlings and saplings caused by Colletotrichum capsici, Fusarium solani and Lasiodiplodia theobromae, stem canker on Eucalyptus spp. caused by Botryosphaeria sp. and leaf blight caused by a Calonectria species.  Management of these diseases will require training of foresters on tree health issues, quarantine and silvicultural practices and initiation of sound breeding and selection programmes.