Diseases of plantation Eucalyptus in Uganda.

Abstract

Survey of diseases of plantation lIgEucalyptusl/Ig was conducted in southern Uganda during June 1999. The aim was to compile a preliminary list of pathogens in planning future plantations and breeding programmes. Root, stem and leaf samples were collected from trees ranging in age from a few months to approximately 10 years. The most commonly isolated pathogen was Lasiodiplodia theobromae , which was frequently associated with stem cankers and die-back. Bacterial wilt, caused by Ralstonia solanacearum , was the most common cause of death of trees less than two years old, in the warmer areas around Kampala. In the eastern part of Uganda, the wilt pathogen Ceratocystis fimbriatal/Ig was isolated from dying E. grandis and, together with L. theobromae , is considered the greatest threat to plantation Eucalyptus in Uganda. Other, less important, pathogens isolated during the survey included a species of lIgMycosphaerellal/Ig from leaf spots and a lIgValsal/Ig species associated with stem cankers.