THE EFFECTS OF Trichoderma IN SURFACE MULCHES SUPPLEMENTED WITH CONIDIAL DRENCHES IN THE DISEASE DEVELOPMENT OF Ganoderma BASAL STEM ROT IN OIL PALM

Biocontrol efficiency of Trichoderma in surface mulches together with conidial drenches on disease suppression of basal stem rot (BSR) caused by Ganoderma boninense in oil palm seedlings was investigated. Surface mulches used were from palm press fibre (PPF). Two isolates of Trichoderma (T. asperellum T9 and T. virens T29) were selected based on the in vitro antagonistic assessment via dual culture followed by poison food agar test. In vivo results indicated disease development was lowest in plants treated with Trichoderma T29 and Trichoderma T9 compared to plants treated with mixed inocula of Trichoderma (T9 and T29), PPF alone and water. Disease development in the plants was assessed using disease severity (DS) and subjected to further analysis with area under the disease progression curve (AUDPC) and epidemic rate (R-L). Disease development was delayed by eight weeks in plants treated with Trichoderma T29 and Trichoderma T9 compared to control treatment. The study also suggests that the potential use of PPF, a biowaste product of palm oil mill as surface mulch, enriched with single Trichoderma species (T9/T29) effectively delayed disease onset in oil palm seedlings.