Current technologies for detection of Ganoderma in oil palm

A survey indicated that Basal Stem Rot (BSR) disease caused by species of Ganoderma, was present in more than 50% of the oil palm fields in Malaysia. Unfortunately, many farmers did not realize that their fields were infected with Ganoderma. More importantly, even in situation where the disease is certain, the plantations failed to recognize the extent of disease incidence nor the specific areas of fields when BSR is a yield-limiting problem. The effect of infection by Ganoderma is the progressive destruction of the basal tissues of the oil palm trunk, but the external symptoms observed in the leaves are those of wilting and malnutrition. The disease can be identified from the dry rot at the base of palm trunk and the presence of typical bracket-shaped basidiomata of the fungal pathogen. The Ganoderma Selective Medium (GSM) has been developed to isolate and confirmed the disease. This medium is very convenient to isolate the fungus from diseased tissue. With GSM, it was possible to detect more (5 to 16%) oil palm infected with Ganoderma not shOWing any obvious symptoms of infection externally using drilling technique. The availability of rapid and accurate diagnostic technique, which is specific and readily adapted to large-scale testing for detecting Ganoderma in oil palm at an early stage of infection, would benefit decision-making for appropriate disease control. The progress on development of technologies for early detection of Ganoderma are being achieved through Enzyme-Linked Immunosorbent Assay-Polyclonal Antibody (ELISA-PAb) and molecular Polymerase Chain Reaction-DNA (PCR-DNA). Work on ELISA-PAb against Ganoderma have been reported, but had been found not specific in detecting Ganoderma due to cross-reaction with saprophytic fungi. Specific PCR-DNA primers for detection of Ganoderma with no cross-reactionwith saprophytic fungi had been developed. These techniques could offer several advantages in providing specificity and sensitivity for detection of Ganoderma in oil palm. Another new technique, sonic tomography technology has been developed; to locate and identify injection of Ganoderma in oil palm also has been developed. The technology is a non-invasive tool designed for assessing tree's decay and degradation. The equipments consist of a Sound Sensor and Tomography software, called PODITOO™. Sound sensors are installed around a circumference of an understudy oil palm stem. Sound wave is emitted on one sensor and time of flight of the sound propagation from the emitter to other sensors is calculated. These sound lines are then used to construct the tomography image of the stem. The detection together with the location and the size of the decay and degradation will enable the expert to perform effective disease treatments on the oil palm trunk. The development of these technologies provided the potential of diagnostic tests for detection of pathogenic Ganoderma in oil palm, which would be valuable not only to the farmers but also to the Quarantine Department.