In vitro assessment of Ca2+, Cu 2+ and salicylic acid (Sa) against Ganoderma boninense

Basal stem rot of oil palm induced by Ganoderma boninense, is a major economically important fungus, that has incurred great losses to the oil palm industry. It has triggered desire for many researchers to find solutions through biological, chemical, and physical controls, as well as using plant activators to carry out proper disease management strategies. At present, nutrients could conceivably be supplied by soil application with a view to control the disease in addition to them being used as fertilisers. Therefore, the objective of this study was to investigate the effect of Ca²+, Cu ²+ and Salicylic acid against G. boninense. In vitro application of nutrients was tested by poison and dipping test for their resistance towards G. boninense. There were four different concentrations for each nutrients and 0 ppm serve as a control. Only combination of (calcium chloride + salicylic acid) and (calcium chloride + copper-EDTA + salicylic acid) showed inhibitory effect more than 50% for the highest concentration in poison media test. On the other hand for dipping test, salicylic acid, (calcium chloride + salicylic acid), (copper-EDTA + salicylic acid) and (calcium chloride + copper-EDTA + salicylic acid) showed percentage inhibition of radial growth (PIRG) values greater than 50% for all concentrations. There was a Significant difference at inhibitory effect at (p<0.05) for salicylic acid but there were no significant differences for rest of above combination and its concentration. The highest efficacy of control was achieved by combination of (calcium chloride + salicylic acid) by an average of 91.25, 94.38, 97.50 and 100.00% for concentration of 500 + 50, 1000 + 100, 1500 + 150, 2000 + 200 ppm respectively and followed by combination of (calcium chloride + copper-EDTA + salicylic acid) by means of 100.00, 100.00, 79.38, 68.75% for concentration 500 + 50 + 50, 1000 + 100 + 100, 1500 + 150 + 150 and 2000 + 200 + 200 ppm respectively. The result implied that the level of inhibition by those combining nutrients will be provided the use as a potential fertilizer to control destructive pathogen of G. boninense in oil palm plantations. Consequences of the in vitro study are a useful reference foundation for further tests in the field and large scale production trials.