Trichoderma yunnanense and T. asperellum as potential biological agents for control of basal stem rot disease in oil palm

Basal Stem Rot (BSR) disease is a main constrain in oil palm cultivation. Ganoderma boninense is known as a causal agent of this disease. The intensity of BSR disease continues to increase in both the vegetative and generative phases of oil palm plantations and causes significant losses. Biological control is one of the BSR disease control techniques and is believed to be able to support sustainable oil palm cultivation. Trichoderma spp. is a group of fungal biological agents commonly used to control BSR disease. This study aims to obtain Trichoderma spp. isolates to be developed further as biocontrol agents for BSR disease. The research stages included isolation, morphology-based identification, antagonist potency testing, characterization, and identification with molecular technique. The results in this research obtained one isolate of Trichoderma strain TSU from oil palm plantation at Pematang Siantar Regency, and one isolate of Trichoderma strain TGLP from oil palm plantation at Musi Banyu Asin Regency, which inhibited the growth of G. boninense was 90.9 and 93.9% respectively through dual culture test. Inhibition tests by volatile compounds showed growth inhibition of G. boninense by both isolates were 55.2 and 70.6%. Both Trichoderma strains have the characteristics of producing chitinase, glucanase, and indole acetic acid. Furthermore, molecular identification showed that the Trichoderma strain TSU was similar to the Trichoderma yunnanense strain CBS121219 with an identity percentage of 99.11%, and Trichoderma TGLP as Trichoderma asperellum strain 1A4 with a percent identity of 99.65%. With their antagonistic ability and characteristics, the two Trichoderma spp. isolates have the potential to be further developed as biological agents for controlling BSR caused by G. boninense.