Pruning (singling) is a common silvicultural practice in commercial Acacia plantations
because these trees tend to have multiple stems. The wounds resulting from pruning are
susceptible to infection by pathogens. Ceratocystis acaciivora and Lasiodiplodia
theobromae have recently been shown to be important pathogens of A. mangium in
Indonesia, where they are commonly associated with wounds on trees. The aim of this
study was to determine the impact of different wound types on infection of A. mangium
and A. crassicarpa by these two pathogens. Isolates of C. acaciivora and L. theobromae,
found to be the most pathogenic in a prior study, were used to inoculate pruning wounds.
Results showed that pruning conducted in a manner to reduce stem damage, resulted in
lower levels of fungal infection. Where pruning resulted in tearing of the bark, there
were greater levels of infection and disease occurred even without artificial inoculation.Inoculation of pruning wounds on A. mangium and A. crassicarpa showed that both
fungi have the potential to cause disease. However, C. acaciivora was most pathogenic.
Results of this study showed conclusively that careful pruning will result in lower levels
of disease in young A. mangium and A. crassicarpa plantations in Indonesia.The Tree Protection Co-operative Programme (TPCP) and the South
African National Research Foundation are thanked for financial support to undertake this
study. The first author also recognizes the support of PT Riau Andalan Pulp and Paper
for support to conduct post graduate studies in South Africa.http://www.nisc.co.za/journals?id=11nf201
