Abstract: Ganoderma boninense is a major pathogen in oil palm
plantations which easily infects basal stems and thus it is difficult to be
eradicated. Fungal endophytes from healthy oil palm tissues can be used as biological
control agents in host plants against G. boninense. For selecting the
antagonist candidates against G. boninense, a simple method of dual culture
assay was used. A total of 526 endophytic fungi were isolated from 531 oil palm
segments in three of plantations location in Medan, North Sumatera province
of Indonesia i.e. Kuala Bekala (KB), Medan Tuntungan (MT) and Medan Johor (MJ).
Overall, fungal isolation rate in oil palm segments was 0.99 and colonization
rate was 77.2% and the highest being found in the KB plantation. From different
sample parts, we found that palm leaf midrib had the highest value of colonization
and isolation rate. Based on six categories in qualitative dual culture assay,
53 isolates showed a high antagonism effect to G. boninense, twenty two
of which were found to have a Colony Growth Inhibition (% CGI) value of more
than 80%. Further studies showed that all 22 isolates exhibited a chitinolytic
activity on Coloidal Chitin Bromcresol purple (CCBp) assay while only ten (crude
extract of liquid culture) inhibited mycelial colony of G. boninense.
From microscopic observation, fungal endophytes attached themselves to the hyphae
of G. boninense at the interaction zone and causing hypae abnormalities
to the pathogen. Almost all selected fungal endophytes potential to be biocontrol
agents against G. boninense belong to the Genera of Trichoderma.