The yield of oil palm of total area 26.9 hectare in period of 25 years in oil palm plantation in Asahan and Simalungun Regency, North Sumatera, Indonesia was studied. The objective was to analyze the impact of planting densityand Ganoderma boninense infectionto the number of fresh fruit bunch and stand palm trees. The yield was harvested three 3 years after planting and subsequently every 2 weeks until 25 years.Oil palm density was determined based on number of palms per hectare. Palm infected by Ganoderma was identifiedsymptomaticallyandcensusof the palms wasconducted every two weeks.The number ofstand palm tree was calculated by comparing the number of dead palms to start stand palm.Each area was plotted 6×8 metres that consisted of 48 palms. The experiment used was randomized complete block design using 3 palms densities i.e high density (160 palms/ha), medium density (143 palms/ha) and low density (128 palms/ha). Five replications were used for each treatment. Oil palmsat high densityboth in Simalungun and Asahan have significant effect (P>0.05)on the yield of fresh fruit bunch compare to medium and low density.Ganoderma infection occured in both areas and no significantly different among densities. The infection started at15 years after planting followed by reducingfresh fruit bunch and stand palm tree. At 25 years after planting the number of stand palm and fresh fruit bunch production at highh density is higher and significantly different (P>0.05) than that of medium and low density.
Keywords: Ganoderma boninense, fresh fruit bunch, oil palm tree, plant density
